856638769 has 8 divisors (see below), whose sum is σ = 1030543040. Its totient is φ = 695616336.

The previous prime is 856638709. The next prime is 856638773. The reversal of 856638769 is 967836658.

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 856638769 - 2⁹ = 856638257 is a prime.

It is a super-2 number, since 2×856638769² = 1467659961107670722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (856638709) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3220314 + ... + 3220579.

It is an arithmetic number, because the mean of its divisors is an integer number (128817880).

Almost surely, 2^856638769 is an apocalyptic number.

It is an amenable number.

856638769 is a deficient number, since it is larger than the sum of its proper divisors (173904271).

856638769 is a wasteful number, since it uses less digits than its factorization.

856638769 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6440919.

The product of its digits is 13063680, while the sum is 58.

The square root of 856638769 is about 29268.3919783783. The cubic root of 856638769 is about 949.7279993221.

The spelling of 856638769 in words is "eight hundred fifty-six million, six hundred thirty-eight thousand, seven hundred sixty-nine".