81 (number)

Eighty-one is a number. It comes between eighty and eighty-two, and is an odd number. It is also a square number.

This article is about the number eighty-one. For the year, see 81.

← 80 81 82 →
← 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-one
Ordinal	81st (eighty-first)
Factorization	34
Greek numeral	ΠΑ´
Roman numeral	LXXXI
Binary	10100012
Ternary	100003
Quaternary	11014
Quinary	3115
Senary	2136
Octal	1218
Duodecimal	6912
Hexadecimal	5116
Vigesimal	4120
Base 36	2936