85 (number)

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

In mathematics
85 is:


 * the product of two prime numbers (5 and 17), and is therefore a semiprime of the form (5.q) where q is prime.
 * specifically, the 24th Semiprime, it being the fourth of the form (5.q).
 * together with 86 and 87, forms the second cluster of three consecutive semiprimes; the first comprising 33, 34, 35.
 * with a prime aliquot sum of 23 in the short aliquot sequence (85,23,1,0).
 * an octahedral number.
 * a centered triangular number.
 * a centered square number.
 * a decagonal number.
 * the smallest number that can be expressed as a sum of two squares, with all squares greater than 1, in two ways, 85 = 92 + 22 = 72 + 62.
 * the length of the hypotenuse of four Pythagorean triangles.
 * a Smith number in decimal.

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
 * 85D/Boethin is a periodic comet

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 recordings 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

 * The year AD 85, 85 BC, or 1985.
 * The Muslim calendar year 85 AH.
 * The atomic number of the chemical element 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
 * 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
 * TK85 was a clone of the Sinclair ZX81 made in Brazil in 1983
 * 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
 * F85 (disambiguation), multiple uses
 * Part of the assignation for the Toyota AE85, commonly referred to as an "eight-five".
 * KiHa 85 series is a diesel Limited express train that ran in Japan until 2023.
 * HC85 series is the successor of KiHa 85 and is a hybrid diesel limited express train.

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