85 (number)

85 (eighty-five) is the natural number following 84 and preceding 86.

← 84 86 → 85
← 80 81 82 83 84 85 86 87 88 89 → List of numbers — Integers 0 10 20 30 40 50 60 70 80 90 →
Cardinal	eighty-five
Ordinal	85th (eighty-fifth)
Numeral system	85
Factorization	$5 \cdot 17$
Divisors	1, 5, 17, 85
Roman numeral	LXXXV
Binary	10101012
Octal	1258
Duodecimal	7112
Hexadecimal	5516

In mathematics

85 is an octahedral number, a centered triangular number, a centered square number, a decagonal number, and a Smith number.

85 is the product of two prime numbers (5 and 17), and is therefore a biprime; specifically, the 24th biprime not counting perfect squares. Together with 86 and 87, it forms the second cluster of three consecutive biprimes.

85 can be expressed as a sum of two squares in two ways, 85= 9² + 2² = 7² + 6²

85 is 1111 (a repunit) in base 4; which is expected, since its two factors 5 and 17 are consecutive Fermat primes, and the base 4 is one less than the smaller factor 5.

The aliquot sum of 85 is 23 within the aliquot sequence (23,1,0) 85 being the second composite number in the 23-aliquot tree.

In astronomy

• Messier object M85 is a magnitude 10.5 lenticular galaxy in the constellation Coma Berenices
• NGC 85 is a galaxy in the constellation Andromeda
• 85 Io is a large main belt asteroid
• 85 Pegasi is a multiple star system in constellation of Pegasus
• 85 Ceti is a variable star in the constellation of Cetus
• 85P/Boethin is a periodic comet
• 85 is the Saros number of the solar eclipse series which began on -170 March 14 and ended on 1110 April (1280.1 years, 72 solar eclipses)
• 85 is also the Saros number of the lunar eclipse series which began on -103 August 2 and ended on 1267 November (1370.3 years, 77 lunar eclipses)

In titles and names

• Federalist No. 85, by Alexander Hamilton, the last of the Federalist Papers' (1788)
• The 85 Ways to Tie a Tie, a book by Thomas Fink and Yong Mao
• 85 Days: The Last Campaign of Robert Kennedy a book by Jules Witcover
• Live/1975–85, an album of live reordings by Bruce Springsteen (1986)
• 80–85 a compilation album by Bad Religion (1991)
• Cupid & Psyche 85, an album by band Scritti Politti (1985)
• 45/85 was a television documentary on World War II
• Minuscule 85, Papyrus 85, Lectionary 85 are early Greek manuscripts of the New Testament
• "85", a 2000 rap single by YoungBloodz, from their album Against Da Grain
• 85°C, a Taiwanese coffee store chain.

In sports

In U.S. college athletics, schools that are members of NCAA Division I are limited to providing athletic scholarships to a maximum of 85 football players in a given season. The specifics vary by the two Division I football subdivisions:

• In the top-level FBS, each player provided with a scholarship may, and almost always does, receive a full scholarship.
• In the second-level FCS, schools are allowed to provide football-related athletic aid equivalent to 63 full scholarships, but this aid may be divided among up to 85 players as the schools see fit.

In other fields

Published in Brazil:
ISBN: 85..

Eighty-five is also:

• The year AD 85, 85 BC, or 1985.
• The Muslim calendar year 85 AH.
• The atomic number of astatine
• The number of the French department Vendée
• The ISBN Group Identifier for books published in Brazil
• The radix of the Ascii85 (sometimes called Base85) binary-to-text encoding
• The IQ and nickname of Aaron in Alien 3
• The number worn by Chad Ochocinco, whose name means "eight five" in Spanish

Moreover:

• Arabigere 85 is a village in India
• E85 fuel is 85% ethanol and 15% conventional gasoline
• MCS-85 was a family of Intel processors including the 8085
• TI-85 was a graphing pocket calculator by Texas Instruments
• KC 85 was a family of small computers built in East Germany in the 1980s
• PMD 85 was a personal computer built in Czechoslovakia in 1985
• Learjet 85 is an all-composite plane being developed by Bombardier Aerospace
• British Rail Class 85, a category of UK train locomotives
• DRG Class 85, a category of German train locomotives
• TK 85 was a clone of the Sinclair ZX81 made in Brazil in 1895
• Lima Site 85 was a battle in the Vietnam War
• A85 is the Dutch Defence in the Encyclopaedia of Chess
• EF 85mm is a photographic camera lens by Canon
• F-85 is a family of Oldsmobile cars

In military technology

• 85mm is a common caliber for cannons
• SU-85 was a Soviet tank
• TR-85 was a Romanian battle tank
• Tu-85 was a prototype Soviet bomber
• ASU-85 a Soviet self-propelled gun
• CZ 85 is a Czech 9mm semiautomatic pistol
• PT-85 is a Korean tank
• 7.62 Tkiv 85 is a Finnish army rifle
• HG 85 is a Swiss fragmentation grenade
• Taurus Model 85, a 9mm revolver made in Brazil

See also

• List of highways numbered 85
• List of highways numbered 85A
• Type 85, a designation of many military equipment

External links

• 85
• Jorge Stolfi, The Hollywood Constant.