685979 has 12 divisors (see below), whose sum is σ = 817776. Its totient is φ = 563472.

The previous prime is 685973. The next prime is 685987. The reversal of 685979 is 979586.

It is not a de Polignac number, because 685979 - 2⁴ = 685963 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (685973) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 12917 + ... + 12969.

It is an arithmetic number, because the mean of its divisors is an integer number (68148).

2⁶⁸⁵⁹⁷⁹ is an apocalyptic number.

685979 is a deficient number, since it is larger than the sum of its proper divisors (131797).

685979 is an equidigital number, since it uses as much as digits as its factorization.

685979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 146 (or 103 counting only the distinct ones).

The product of its digits is 136080, while the sum is 44.

The square root of 685979 is about 828.2384922231. The cubic root of 685979 is about 88.1935735399.

The spelling of 685979 in words is "six hundred eighty-five thousand, nine hundred seventy-nine".