81056810656 has 12 divisors (see below), whose sum is σ = 159580596042. Its totient is φ = 40528405312.

The previous prime is 81056810633. The next prime is 81056810677. The reversal of 81056810656 is 65601865018.

It can be written as a sum of positive squares in only one way, i.e., 80576499600 + 480311056 = 283860^2 + 21916^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1266512635 + ... + 1266512698.

Almost surely, 2^81056810656 is an apocalyptic number.

It is an amenable number.

81056810656 is a deficient number, since it is larger than the sum of its proper divisors (78523785386).

81056810656 is a wasteful number, since it uses less digits than its factorization.

81056810656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2533025343 (or 2533025335 counting only the distinct ones).

The product of its (nonzero) digits is 345600, while the sum is 46.

The spelling of 81056810656 in words is "eighty-one billion, fifty-six million, eight hundred ten thousand, six hundred fifty-six".