686646831 has 12 divisors (see below), whose sum is σ = 991372488. Its totient is φ = 422551584.

The previous prime is 686646817. The next prime is 686646839. The reversal of 686646831 is 138646686.

It is not a de Polignac number, because 686646831 - 2⁶ = 686646767 is a prime.

It is a super-2 number, since 2×686646831² = 942967741044685122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686646839) 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 11 ways as a sum of consecutive naturals, for example, 676660 + ... + 677673.

It is an arithmetic number, because the mean of its divisors is an integer number (82614374).

Almost surely, 2^686646831 is an apocalyptic number.

686646831 is a deficient number, since it is larger than the sum of its proper divisors (304725657).

686646831 is a wasteful number, since it uses less digits than its factorization.

686646831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1354362 (or 1354349 counting only the distinct ones).

The product of its digits is 995328, while the sum is 48.

The square root of 686646831 is about 26203.9468592042. The cubic root of 686646831 is about 882.2218437650.

The spelling of 686646831 in words is "six hundred eighty-six million, six hundred forty-six thousand, eight hundred thirty-one".