856861431 has 16 divisors (see below), whose sum is σ = 1162739424. Its totient is φ = 561199104.

The previous prime is 856861427. The next prime is 856861493. The reversal of 856861431 is 134168658.

It is not a de Polignac number, because 856861431 - 2² = 856861427 is a prime.

It is a super-2 number, since 2×856861431² = 1468423023870735522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (856861631) 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 15 ways as a sum of consecutive naturals, for example, 29121 + ... + 50613.

It is an arithmetic number, because the mean of its divisors is an integer number (72671214).

Almost surely, 2^856861431 is an apocalyptic number.

856861431 is a deficient number, since it is larger than the sum of its proper divisors (305877993).

856861431 is a wasteful number, since it uses less digits than its factorization.

856861431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21730.

The product of its digits is 138240, while the sum is 42.

The square root of 856861431 is about 29272.1955274967. The cubic root of 856861431 is about 949.8102782726.

The spelling of 856861431 in words is "eight hundred fifty-six million, eight hundred sixty-one thousand, four hundred thirty-one".