686381656 has 32 divisors (see below), whose sum is σ = 1321472880. Its totient is φ = 334028800.

The previous prime is 686381629. The next prime is 686381711. The reversal of 686381656 is 656183686.

It is a super-2 number, since 2×686381656² = 942239555386604672, which contains 22 as substring.

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, 150936 + ... + 155416.

Almost surely, 2^686381656 is an apocalyptic number.

It is an amenable number.

686381656 is a deficient number, since it is larger than the sum of its proper divisors (635091224).

686381656 is a wasteful number, since it uses less digits than its factorization.

686381656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4995 (or 4991 counting only the distinct ones).

The product of its digits is 1244160, while the sum is 49.

The square root of 686381656 is about 26198.8865412254. The cubic root of 686381656 is about 882.1082612125.

The spelling of 686381656 in words is "six hundred eighty-six million, three hundred eighty-one thousand, six hundred fifty-six".