1 million digits of PI 1 billion digits of PI Mandelbrot set Explorer

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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