681309808 has 20 divisors (see below), whose sum is σ = 1325809240. Its totient is φ = 339165504.

The previous prime is 681309781. The next prime is 681309817. The reversal of 681309808 is 808903186.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 89310 + ... + 96637.

It is an arithmetic number, because the mean of its divisors is an integer number (66290462).

Almost surely, 2^681309808 is an apocalyptic number.

It is an amenable number.

681309808 is a deficient number, since it is larger than the sum of its proper divisors (644499432).

681309808 is a wasteful number, since it uses less digits than its factorization.

681309808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 186184 (or 186178 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 43.

The square root of 681309808 is about 26101.9119606208. The cubic root of 681309808 is about 879.9301804110.

The spelling of 681309808 in words is "six hundred eighty-one million, three hundred nine thousand, eight hundred eight".