685655679 has 48 divisors (see below), whose sum is σ = 1034467200. Its totient is φ = 402725376.

The previous prime is 685655651. The next prime is 685655701. The reversal of 685655679 is 976556586.

It is not a de Polignac number, because 685655679 - 2²⁰ = 684607103 is a prime.

It is a Smith number, since the sum of its digits (57) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (57).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (685655479) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1762417 + ... + 1762805.

It is an arithmetic number, because the mean of its divisors is an integer number (21551400).

Almost surely, 2^685655679 is an apocalyptic number.

685655679 is a deficient number, since it is larger than the sum of its proper divisors (348811521).

685655679 is a wasteful number, since it uses less digits than its factorization.

685655679 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 552 (or 535 counting only the distinct ones).

The product of its digits is 13608000, while the sum is 57.

The square root of 685655679 is about 26185.0277639723. The cubic root of 685655679 is about 881.7971533355.

The spelling of 685655679 in words is "six hundred eighty-five million, six hundred fifty-five thousand, six hundred seventy-nine".