685915840 has 28 divisors (see below), whose sum is σ = 1633337856. Its totient is φ = 274366208.

The previous prime is 685915829. The next prime is 685915843. The reversal of 685915840 is 48519586.

It is a Smith number, since the sum of its digits (46) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (685915843) by changing a digit.

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, 1071424 + ... + 1072063.

Almost surely, 2^685915840 is an apocalyptic number.

It is an amenable number.

685915840 is an abundant number, since it is smaller than the sum of its proper divisors (947422016).

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

685915840 is a wasteful number, since it uses less digits than its factorization.

685915840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2143504 (or 2143494 counting only the distinct ones).

The product of its (nonzero) digits is 345600, while the sum is 46.

The square root of 685915840 is about 26189.9950362729. The cubic root of 685915840 is about 881.9086671400.

The spelling of 685915840 in words is "six hundred eighty-five million, nine hundred fifteen thousand, eight hundred forty".