- 11 (number)
Number|number = 11
range = 10s
cardinal = eleven
ordinal = th
ordinal text =
factorization = prime
divisor = 1, 11
roman = XI
greek prefix = (from Greek)
latin prefix = (from
bin = 1011
oct = 102
duo = B
hex = B
11 (eleven) is the
natural numberfollowing 10 and preceding 12. It is the first number which cannot be represented by a humancounting his or her eight fingers and two thumbs additively (although it can be represented in a variety of other ways using human bodily parts, such as counting additively with the twenty digits including the toes, using the thumb to count the finger phalanges of one hand additively up to twelve, or using the fingers in one hand to count up to fifteen binarily). Eleven is the smallest positive integer requiring three syllables in English, and it is also the largest prime number with a single-morpheme name in this language (although etymologically the word "eleven" originated from a Germanic compound *"ainlif" meaning "one left" [http://www.bartleby.com/61/62/E0086200.html] ).
Eleven is the 5th smallest
prime number. It is the smallest two-digit prime number in the decimalbase; as well as, of course, in undecimal(where it is the smallest two-digit number). It is also the smallest three-digit prime in ternary, and the smallest four-digit prime in binary, but a single-digit prime in bases larger than ten, such as duodecimal, hexadecimal, vigesimaland sexagesimal. 11 is the fourth Sophie Germain prime, the third safe prime, the fourth Lucas prime, and the first repunit prime. Although it is necessary for n to be prime for 2n-1 to be a Mersenne prime, the converse is not true: 211 - 1 = 2047 which is 23 × 89. The next prime is 13, with which it comprises a twin prime. 11 is an Eisenstein primewith no imaginary part and real part of the form . Displayed on a calculator, 11 is a strobogrammatic primeand a dihedral primebecause it reads the same whether the calculator is turned upside down or reflected on a mirror, or both.
Because it has a reciprocal of unique period length among primes, 11 is the second
unique prime. 11 goes into 99 exactly 9 times, so vulgar fractions with 11 in the denominatorhave two digit repeating sequences in their decimalexpansions. Multiples of eleven by one-digit numbers all have double digits: 00 (=0), 11, 22, 33, 44 . . .
Eleven is the
Aliquot sumof one number, the discrete biprime21 and is the base of the 11-aliquot tree.
As 11 is the smallest factor of the first eleven terms of the
Euclid-Mullin sequence, it is the twelfth term.
polygonis called a hendecagonor undecagon.
In both base 6 and base 8, the smallest prime with a composite sum of digits is 11.
In base 10, there is a simple test to determine if an integer is divisible by 11: take every digit of the number located in odd position and add them up, then take the remaining digits and add them up. If the difference between the two sums is a multiple of 11, including 0, then the number is divisible by 11. For instance, if the number is 65,637 then (6 + 6 + 7) - (5 + 3) = 19 - 8 = 11, so 65,637 is divisible by eleven. This technique also works with groups of digits rather than individual digits, so long as the number of digits in each group is odd, although not all groups have to have the same number of digits. For instance, if one uses three digits in each group, one gets from 65,637 the calculation (065) - 637 = -572, which is divisible by eleven.
Another test for divisibility is to separate a number into groups of two consecutive digits (adding a leading zero if there is an odd number of digits), and then add up the numbers so formed; if the result is divisible by eleven, the number is divisible by eleven. For instance, if the number is 65,637, 06 + 56 + 37 = 99, which is divisible by eleven, so 65,637 is divisible by eleven. This also works by adding a trailing zero instead of a leading one: 65 + 63 + 70 = 198, which is divisible by eleven. This also works with larger groups of digits, providing that each group has an even number of digits (not all groups have to have the same number of digits).
An easy way of
multiplying numbers by 11 in base 10 is:If the number has:
*1 digit - Replicate the digit (so 2 x 11 becomes 22).
*2 digits - Add the 2 digits together and place the result in the middle (so 47 x 11 becomes 4 (11) 7 or 4 (10+1) 7 or (4+1) 1 7 or 517).
*3 digits - Keep the first digit in its place for the result's first digit, add the first and second digits together to form the result's second digit, add the second and third digits together to form the result's third digit, and keep the third digit as the result's fourth digit. For any resulting numbers greater than 9, carry the 1 to the left. Example 1: 123 x 11 becomes 1 (1+2) (2+3) 3 or 1353. Example 2: 481 x 11 becomes 4 (4+8) (8+1) 1 or 4 (10+2) 9 1 or (4+1) 2 9 1 or 5291.
*4 or more digits - Follow the same pattern as for 3 digits.
In base 10, 11 is the only integer that is not a
In base thirteen and higher bases (such as
hexadecimal), eleven is represented as B, where ten is A. In duodecimal, however, eleven is sometimes represented as E and ten as T.
Multiplied by num/neg|1, eleven is a
There are 11 orthogonal curvilinear
coordinate systems(to within a conformal symmetry) in which the 3-variable Helmholtz equationcan be solved using the separation of variablestechnique.
List of basic calculations
List of basic operations that make 11
atomic numberof sodium.
*In chemistry, Group 11 includes the three coinage metals
copper, silver, and goldknown from antiquity.
*The number of
spacetime dimensions in M-theory.
Apollo 11was the first manned spacecraft to land on the Moon.
*The approximate periodicity of a
sunspot cycleis 11 years.
Messier objectM11, a magnitude 7.0 open clusterin the constellation Scutum, also known as the Wild Duck Cluster.
New General Catalogue[http://www.ngcic.org/ object] NGC 11, a spiral galaxyin the constellationAndromeda
Saros[http://sunearth.gsfc.nasa.gov/eclipse/LEsaros/LEsaros1-175.html number] of the solar eclipseseries which began on -2511 December 26and ended on -1158 March 18. The duration of Saros series 11 was 1352.2 years, and it contained 76 solar eclipses.
*The Saros [http://sunearth.gsfc.nasa.gov/eclipse/LEsaros/LEsaros1-175.html number] of the
lunar eclipseseries which began on -2389 June 19and ended on -1037 September 8. The duration of Saros series 11 was 1352.2 years, and it contained 76 lunar eclipses.
*The 11th moon of Jupiter is Himalia.
*The interval of an
octaveand a fourth is an eleventh. A complete eleventh chord has almost every note of a diatonic scale.
*The number of thumb keys on a
bassoon, not counting the whisper key. (A few bassoons have a twelfth thumb key.)
Spinal Tap's amplifiers go up to eleven, every other bands' just go to ten, but it doesn't actually amplify the sound any greater.
*Maria Taylor's Debut solo album is entitled 11:11
*The All-American Rejects have a song on the CD Move Along that is called 11:11
Andrew Birdhas a song called 11:11
*The title of
Bryan Adams' newest album is 11.
Jimmy, by the band Toolmentions the number 11, in reference to a stroke suffered by lead singer Maynard James Keenan's mother when he was 11 years old; it also refers to the number of dimensions in M Theoryand String Theory.
There are eleven players on a soccer team on the field at a time as well as in a
cricketteam. Within a school or college, the phrases "the football XI" and "the cricket XI" generally refer to the first (best) team currently playing.Other teams are often referred to as "the second XI" etc.
Also in soccer, in the German language (and possibly others, in countries that predominantly use the metric system) a penalty kick is referred to as "Elfmeter" because the penalty spot is approximately 11m (precisely 12 yards) from the goal line. Historically, in the Pyramid formation that position names are taken from, a left wing-forward in football wears number 11. In the modern game, especially using the 4-4-2 formation, it is worn by a left-sided
midfielder. Less commonly a strikerwill wear the shirt.
There are eleven players in a
field hockeyteam. The player wearing 11 will usually play on the left-hand side, as in soccer.
American footballteam also has eleven players on the field at one time during play. 11 is also worn by quarterbacks, kickers, punter and wide receivers in American football's NFL. The only NFL team that has retired the #11 is the New York Giants, in honor of quarterback Phil Simms.
rugby unionthe left wing wears the 11 shirt. Jonah Lomuwore the number when he played for the All Blacksas he played left wing (see rugby union above).
rugby league, the 11 shirt is worn by a second-row forward.
In cricket, 11 is the number of players from the fielding (or bowling) side on the field of play at any one time. The eleventh batsman is usually the weakest batsman, at the end of the tail. He is primarily in the team for his bowling abilities.
The car number 11 was driven by
Ayrton Sennaas he won the 1988 Formula OneWorld Championship. Also Darrell Waltripand Cale Yarboroughused the number when they won their NASCAR Winston Cup Serieschampionships.
In the military
*The number of guns in a gun
saluteto U.S. Army, Air Force and Marine Corps Brigadier Generals, and to Navy and Coast Guard Rear Admirals Lower Half.
Military Occupational Specialty(MOS) designator given to US Army Infantry (AKA 11 Series, or 11B, 11C, 11D, 11H, 11M, etc)
*The number of General Orders for Sentries in the Marine Corps and
United States Navy.
*A page in the Service Record Book of an enlisted Marine for writing down disciplinary actions.
World War Iended with an Armistice on November 11, 1918, which went into effect at 11:00 am-the 11th hour on the 11th day of the 11th month of the year. Armistice Dayis still observed on November 11of each year, although it is now called Veteran's Dayin the United States and Remembrance Dayin the Commonwealth of Nationsand parts of Europe.
Mozilla Firefox, Opera, Konquerorfor KDE, and Internet Explorer 4and later [ [http://www.microsoft.com/enable/products/KeyboardSearch_IE4.aspx Keyboard Shortcuts for Internet Explorer 4 ] ] for Windows, the function keyF11 key toggles full screen viewing mode. In Mac OS X, F11 hides all open windows.
* The windowing system for
Unixcomputers is known as X11.
* The stylized maple leaf on the
Flag of Canadahas eleven points.
* The Canadian one-dollar coin is a
hendecagon, an eleven-sided polygon.
* Clocks depicted on Canadian currency, for example the
Canadian fifty-dollar bill, show 11:00.
* Eleven denominations of Canadian currency are produced in large quantities.
* Due to Canada's federal nature, eleven legally distinct Crowns effectively exist in the country, with the Monarch being represented separately in each province, as well as at the federal level.
In other fields
*Three films -- "Ben-Hur" (1959), "Titanic" (1997), and "" (2003) -- have each won eleven
Academy Awards, including Best Pictureof their respective years.
*The number eleven is important in
numerology, as it is the first of the "Master Numbers".
*Being only one hour before 12:00—
midnight—the " eleventh hour" means the last possible moment to take care of something, and often implies a situation of urgent danger or emergency (see Doomsday clock).
Astrology, Aquarius is the 11th astrological signof the Zodiac.
*In the film "
This Is Spinal Tap," guitarist Nigel Tufnelproudly shows off an amplifierwith top settings of 11, higher than the traditional 10. The phrase " Up to eleven" or "These go to eleven" in popular culturehas come to refer to anything capable of being exploited to its utmost abilities, or to exceed them, such as a sound volume control. Similarly, the expression "turning it up to eleven" may refer to the act of taking something to an extreme. In 2002 the phrase entered the Shorter Oxford English Dictionarywith the definition "up to maximum volume" [http://www.timesonline.co.uk/printFriendly/0%2C%2C1-3564-427663%2C00.html] .
Ocean's Eleven" is the name of two American films.
*In Basque, "hamaika" ("eleven") has the double meaning of "
infinite", probably from "amaigabe", "endless", as in "Hamaika aldiz etortzeko esan dizut!" ("I told you infinite/eleven times to come!").
American Airlines flight 11, a Boston- Los Angelesflight which crashed into the North Tower of the World Trade Center after being hijacked by terrorists in New York, New Yorkon September 11, 2001.
number 11 busis a low-cost way of sightseeingin London
* In the game of
blackjack, an Ace can be counted as either one or eleven, whichever is more advantageous for the player.
* Sadra Azizi, nominee for Grand Marshal of RPI, ran on the 11 platform.
* 11 is the number of dimensions in M theory
* 11 is the number of the French department
Wikimedia Foundation. 2010.