811865856 has 36 divisors (see below), whose sum is σ = 2160749192. Its totient is φ = 270621696.

The previous prime is 811865833. The next prime is 811865861. The reversal of 811865856 is 658568118.

It is a super-2 number, since 2×811865856² = 1318252336277225472, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 527791 + ... + 529326.

Almost surely, 2^811865856 is an apocalyptic number.

It is an amenable number.

811865856 is an abundant number, since it is smaller than the sum of its proper divisors (1348883336).

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

811865856 is a wasteful number, since it uses less digits than its factorization.

811865856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1057136 (or 1057122 counting only the distinct ones).

The product of its digits is 460800, while the sum is 48.

The square root of 811865856 is about 28493.2598345644. The cubic root of 811865856 is about 932.8849619621.

The spelling of 811865856 in words is "eight hundred eleven million, eight hundred sixty-five thousand, eight hundred fifty-six".