685689 has 16 divisors (see below), whose sum is σ = 966144. Its totient is φ = 432000.

The previous prime is 685679. The next prime is 685697. The reversal of 685689 is 986586.

It is not a de Polignac number, because 685689 - 2⁹ = 685177 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 685689.

It is not an unprimeable number, because it can be changed into a prime (685609) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6739 + ... + 6839.

It is an arithmetic number, because the mean of its divisors is an integer number (60384).

2⁶⁸⁵⁶⁸⁹ is an apocalyptic number.

It is an amenable number.

685689 is a deficient number, since it is larger than the sum of its proper divisors (280455).

685689 is a wasteful number, since it uses less digits than its factorization.

685689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 208.

The product of its digits is 103680, while the sum is 42.

The square root of 685689 is about 828.0634033696. The cubic root of 685689 is about 88.1811437418.

The spelling of 685689 in words is "six hundred eighty-five thousand, six hundred eighty-nine".