81565933081007 has 2 divisors, whose sum is σ = 81565933081008. Its totient is φ = 81565933081006.

The previous prime is 81565933080851. The next prime is 81565933081019. The reversal of 81565933081007 is 70018033956518.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81565933081007 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81565933081037) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40782966540503 + 40782966540504.

It is an arithmetic number, because the mean of its divisors is an integer number (40782966540504).

Almost surely, 2^{81565933081007} is an apocalyptic number.

81565933081007 is a deficient number, since it is larger than the sum of its proper divisors (1).

81565933081007 is an equidigital number, since it uses as much as digits as its factorization.

81565933081007 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5443200, while the sum is 56.

The spelling of 81565933081007 in words is "eighty-one trillion, five hundred sixty-five billion, nine hundred thirty-three million, eighty-one thousand, seven".