685668 has 12 divisors (see below), whose sum is σ = 1599920. Its totient is φ = 228552.

The previous prime is 685649. The next prime is 685669. The reversal of 685668 is 866586.

685668 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (12).

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (685669) by changing a digit.

685668 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 28558 + ... + 28581.

2⁶⁸⁵⁶⁶⁸ is an apocalyptic number.

It is an amenable number.

685668 is an abundant number, since it is smaller than the sum of its proper divisors (914252).

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

685668 is a wasteful number, since it uses less digits than its factorization.

685668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57146 (or 57144 counting only the distinct ones).

The product of its digits is 69120, while the sum is 39.

The square root of 685668 is about 828.0507230840. The cubic root of 685668 is about 88.1802435169.

The spelling of 685668 in words is "six hundred eighty-five thousand, six hundred sixty-eight".