# Number 81

## Properties of the number 81

 Prime Factorization 34 Divisors 1, 3, 9, 27, 81 Count of divisors 5 Sum of divisors 121 Previous integer 80 Next integer 82 Is prime? NO Previous prime 79 Next prime 83 81st prime number ↻ calculating, please wait Is a Fibonacci number? NO 81st Fibonacci number 37889062373143906 Zeckendorf representation 55 + 21 + 5 Is a Pell number? NO Is a regular number? YES Is a perfect number? NO Is a perfect square number? YES Is a perfect cube number? NO Is power of 2? NO Is power of 3? YES Factorial 81! 5.7971260207474E+120 Square 812 6561 Square root √81 9 Cube 813 531441 Cubic root ∛81 4.3267487109222 Natural logarithm 4.3944491546724 Decimal logarithm 1.9084850188786

## Trigonometry of the number 81

 81 modulo 360° 81° Sine of 81 radians -0.62988799427445 Cosine of 81 radians 0.77668598202163 Tangent of 81 radians -0.81099441583189 Sine of 81 degrees 0.98768834059514 Cosine of 81 degrees 0.15643446504023 Tangent of 81 degrees 6.313751514675 81 degrees in radiants 1.4137166941154 81 radiants in degrees 4640.9581405597

## Base conversion of the number 81

 Binary 1010001 Octal 121 Duodecimal 69 Hexadecimal 51

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