685657664 has 28 divisors (see below), whose sum is σ = 1362899484. Its totient is φ = 342249984.

The previous prime is 685657649. The next prime is 685657681. The reversal of 685657664 is 466756586.

It can be written as a sum of positive squares in 2 ways, for example, as 20430400 + 665227264 = 4520^2 + 25792^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30494 + ... + 47970.

Almost surely, 2^685657664 is an apocalyptic number.

685657664 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

685657664 is a deficient number, since it is larger than the sum of its proper divisors (677241820).

685657664 is a wasteful number, since it uses less digits than its factorization.

685657664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18102 (or 18092 counting only the distinct ones).

The product of its digits is 7257600, while the sum is 53.

The square root of 685657664 is about 26185.0656672845. The cubic root of 685657664 is about 881.7980042804.

The spelling of 685657664 in words is "six hundred eighty-five million, six hundred fifty-seven thousand, six hundred sixty-four".