681591864 has 32 divisors (see below), whose sum is σ = 1793664000. Its totient is φ = 215239392.

The previous prime is 681591853. The next prime is 681591877. The reversal of 681591864 is 468195186.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 746904 + ... + 747815.

It is an arithmetic number, because the mean of its divisors is an integer number (56052000).

Almost surely, 2^681591864 is an apocalyptic number.

It is an amenable number.

681591864 is an abundant number, since it is smaller than the sum of its proper divisors (1112072136).

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

681591864 is a wasteful number, since it uses less digits than its factorization.

681591864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1494747 (or 1494743 counting only the distinct ones).

The product of its digits is 414720, while the sum is 48.

The square root of 681591864 is about 26107.3143773924. The cubic root of 681591864 is about 880.0515913279.

The spelling of 681591864 in words is "six hundred eighty-one million, five hundred ninety-one thousand, eight hundred sixty-four".