685664 has 24 divisors (see below), whose sum is σ = 1543248. Its totient is φ = 293760.

The previous prime is 685649. The next prime is 685669. The reversal of 685664 is 466586.

It is a nialpdrome in base 16.

It is a congruent number.

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

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1307 + ... + 1754.

It is an arithmetic number, because the mean of its divisors is an integer number (64302).

2⁶⁸⁵⁶⁶⁴ is an apocalyptic number.

It is an amenable number.

685664 is an abundant number, since it is smaller than the sum of its proper divisors (857584).

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

685664 is a wasteful number, since it uses less digits than its factorization.

685664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3078 (or 3070 counting only the distinct ones).

The product of its digits is 34560, while the sum is 35.

The square root of 685664 is about 828.0483077695. The cubic root of 685664 is about 88.1800720434.

The spelling of 685664 in words is "six hundred eighty-five thousand, six hundred sixty-four".