686729856 has 64 divisors (see below), whose sum is σ = 1883001600. Its totient is φ = 221521920.

The previous prime is 686729803. The next prime is 686729867. The reversal of 686729856 is 658927686.

It is a tau number, because it is divible by the number of its divisors (64).

It is a junction number, because it is equal to n+sod(n) for n = 686729796 and 686729805.

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 7 ways as a sum of consecutive naturals, for example, 16941 + ... + 40748.

It is an arithmetic number, because the mean of its divisors is an integer number (29421900).

Almost surely, 2^686729856 is an apocalyptic number.

It is an amenable number.

686729856 is an abundant number, since it is smaller than the sum of its proper divisors (1196271744).

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

686729856 is a wasteful number, since it uses less digits than its factorization.

686729856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57737 (or 57725 counting only the distinct ones).

The product of its digits is 8709120, while the sum is 57.

The square root of 686729856 is about 26205.5310192333. The cubic root of 686729856 is about 882.2573998972.

The spelling of 686729856 in words is "six hundred eighty-six million, seven hundred twenty-nine thousand, eight hundred fifty-six".