81565007 has 2 divisors, whose sum is σ = 81565008. Its totient is φ = 81565006.

The previous prime is 81564943. The next prime is 81565019. The reversal of 81565007 is 70056518.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81565007 - 2⁶ = 81564943 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81565067) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40782503 + 40782504.

It is an arithmetic number, because the mean of its divisors is an integer number (40782504).

Almost surely, 2^81565007 is an apocalyptic number.

81565007 is a deficient number, since it is larger than the sum of its proper divisors (1).

81565007 is an equidigital number, since it uses as much as digits as its factorization.

81565007 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8400, while the sum is 32.

The square root of 81565007 is about 9031.3347297063. The cubic root of 81565007 is about 433.6785670250.

The spelling of 81565007 in words is "eighty-one million, five hundred sixty-five thousand, seven".