685865856 has 64 divisors (see below), whose sum is σ = 1961986320. Its totient is φ = 211034112.

The previous prime is 685865821. The next prime is 685865881. The reversal of 685865856 is 658568586.

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

It is a super-2 number, since 2×685865856² = 940823944853225472, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 685865796 and 685865805.

It is a congruent number.

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, 63705 + ... + 73688.

Almost surely, 2^685865856 is an apocalyptic number.

It is an amenable number.

685865856 is an abundant number, since it is smaller than the sum of its proper divisors (1276120464).

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

685865856 is a wasteful number, since it uses less digits than its factorization.

685865856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137423 (or 137411 counting only the distinct ones).

The product of its digits is 13824000, while the sum is 57.

The square root of 685865856 is about 26189.0407613566. The cubic root of 685865856 is about 881.8872444955.

The spelling of 685865856 in words is "six hundred eighty-five million, eight hundred sixty-five thousand, eight hundred fifty-six".