686640324864 has 288 divisors, whose sum is σ = 2101394211840. Its totient is φ = 197385560064.

The previous prime is 686640324847. The next prime is 686640324889. The reversal of 686640324864 is 468423046686.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 9839407 + ... + 9908945.

It is an arithmetic number, because the mean of its divisors is an integer number (7296507680).

Almost surely, 2^686640324864 is an apocalyptic number.

686640324864 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 686640324864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1050697105920).

686640324864 is an abundant number, since it is smaller than the sum of its proper divisors (1414753886976).

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

686640324864 is a wasteful number, since it uses less digits than its factorization.

686640324864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69637 (or 69623 counting only the distinct ones).

The product of its (nonzero) digits is 31850496, while the sum is 57.

The spelling of 686640324864 in words is "six hundred eighty-six billion, six hundred forty million, three hundred twenty-four thousand, eight hundred sixty-four".