81312502635 has 48 divisors (see below), whose sum is σ = 173466681024. Its totient is φ = 34312087296.

The previous prime is 81312502603. The next prime is 81312502679. The reversal of 81312502635 is 53620521318.

81312502635 is a `hidden beast` number, since 8 + 1 + 3 + 12 + 5 + 0 + 2 + 635 = 666.

It is not a de Polignac number, because 81312502635 - 2⁵ = 81312502603 is a prime.

It is a super-2 number, since 2×81312502635² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81312502635.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 9924172 + ... + 9932361.

It is an arithmetic number, because the mean of its divisors is an integer number (3613889188).

Almost surely, 2^81312502635 is an apocalyptic number.

81312502635 is an abundant number, since it is smaller than the sum of its proper divisors (92154178389).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81312502635 is a wasteful number, since it uses less digits than its factorization.

81312502635 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19856564 (or 19856561 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 36.

The spelling of 81312502635 in words is "eighty-one billion, three hundred twelve million, five hundred two thousand, six hundred thirty-five".