635664 has 80 divisors (see below), whose sum is σ = 1874880. Its totient is φ = 184320.

The previous prime is 635659. The next prime is 635689. The reversal of 635664 is 466536.

It is an unprimeable number.

635664 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 15 ways as a sum of consecutive naturals, for example, 15484 + ... + 15524.

It is an arithmetic number, because the mean of its divisors is an integer number (23436).

2⁶³⁵⁶⁶⁴ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 635664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (937440).

635664 is an abundant number, since it is smaller than the sum of its proper divisors (1239216).

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

635664 is a wasteful number, since it uses less digits than its factorization.

635664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88 (or 82 counting only the distinct ones).

The product of its digits is 12960, while the sum is 30.

The square root of 635664 is about 797.2853943225. The cubic root of 635664 is about 85.9823291618.

The spelling of 635664 in words is "six hundred thirty-five thousand, six hundred sixty-four".