85 (number)
Natural number
From Wikipedia, the free encyclopedia
85 (eighty-five) is the natural number following 84 and preceding 86.
| ||||
|---|---|---|---|---|
| Cardinal | eighty-five | |||
| Ordinal | 85th (eighty-fifth) | |||
| Factorization | 5 × 17 | |||
| Divisors | 1, 5, 17, 85 | |||
| Greek numeral | ΠΕ´ | |||
| Roman numeral | LXXXV, lxxxv | |||
| Binary | 10101012 | |||
| Ternary | 100113 | |||
| Senary | 2216 | |||
| Octal | 1258 | |||
| Duodecimal | 7112 | |||
| Hexadecimal | 5516 | |||
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.[1]
- with a prime aliquot sum of 23 in the short aliquot sequence (85,23,1,0).
- an octahedral number.[2]
- a centered triangular number.[3]
- a centered square number.[4]
- a decagonal number.[5]
- 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.[6]
- the length of the hypotenuse of four Pythagorean triangles.
- a Smith number in decimal.[7]
In other fields
- The radix of the Ascii85 (sometimes called Base85) binary-to-text encoding
- Part of the assignation for the Toyota AE85, commonly referred to as an "eight-five".
