686806638 has 48 divisors (see below), whose sum is σ = 1599969024. Its totient is φ = 195973680.

The previous prime is 686806597. The next prime is 686806639. The reversal of 686806638 is 836608686.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686806639) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 436393 + ... + 437963.

It is an arithmetic number, because the mean of its divisors is an integer number (33332688).

Almost surely, 2^686806638 is an apocalyptic number.

686806638 is an abundant number, since it is smaller than the sum of its proper divisors (913162386).

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

686806638 is a wasteful number, since it uses less digits than its factorization.

686806638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3077 (or 3070 counting only the distinct ones).

The product of its (nonzero) digits is 1990656, while the sum is 51.

The square root of 686806638 is about 26206.9959743577. The cubic root of 686806638 is about 882.2902798633.

The spelling of 686806638 in words is "six hundred eighty-six million, eight hundred six thousand, six hundred thirty-eight".