811856857 has 8 divisors (see below), whose sum is σ = 932964032. Its totient is φ = 692031600.

The previous prime is 811856831. The next prime is 811856863. The reversal of 811856857 is 758658118.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 811856857 - 2²³ = 803468249 is a prime.

It is a super-2 number, since 2×811856857² = 1318223112515836898, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 811856857.

It is not an unprimeable number, because it can be changed into a prime (811856557) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 319119 + ... + 321652.

It is an arithmetic number, because the mean of its divisors is an integer number (116620504).

Almost surely, 2^811856857 is an apocalyptic number.

It is an amenable number.

811856857 is a deficient number, since it is larger than the sum of its proper divisors (121107175).

811856857 is a wasteful number, since it uses less digits than its factorization.

811856857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 640959.

The product of its digits is 537600, while the sum is 49.

The square root of 811856857 is about 28493.1019195875. The cubic root of 811856857 is about 932.8815151436.

The spelling of 811856857 in words is "eight hundred eleven million, eight hundred fifty-six thousand, eight hundred fifty-seven".