81565933080851 has 2 divisors, whose sum is σ = 81565933080852. Its totient is φ = 81565933080850.

The previous prime is 81565933080833. The next prime is 81565933081007. The reversal of 81565933080851 is 15808033956518.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81565933080851 - 2²⁶ = 81565865971987 is a prime.

It is not a weakly prime, because it can be changed into another prime (81565933020851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40782966540425 + 40782966540426.

It is an arithmetic number, because the mean of its divisors is an integer number (40782966540426).

Almost surely, 2^{81565933080851} is an apocalyptic number.

81565933080851 is a deficient number, since it is larger than the sum of its proper divisors (1).

81565933080851 is an equidigital number, since it uses as much as digits as its factorization.

81565933080851 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 31104000, while the sum is 62.

The spelling of 81565933080851 in words is "eighty-one trillion, five hundred sixty-five billion, nine hundred thirty-three million, eighty thousand, eight hundred fifty-one".