81: eighty one

numbers

Square root of 81 : 9
Square of 81 :6561
81 in Roman: LXXXI
81 in Binary: 1010001
81 in Octal: 121
81 in Hexadecimal: 51
Prime Factors of 81 : 3⁴
81 is a 4-gonal number
81 is a 7-gonal number
81 is a 28-gonal number