637664 has 12 divisors (see below), whose sum is σ = 1255464. Its totient is φ = 318816.

The previous prime is 637657. The next prime is 637669. The reversal of 637664 is 466736.

637664 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (32), and also a Moran number because the ratio is a prime number: 19927 = 637664 / (6 + 3 + 7 + 6 + 6 + 4).

It is a self number, because there is not a number n which added to its sum of digits gives 637664.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (637669) by changing a digit.

637664 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 as a sum of consecutive naturals, namely, 9932 + ... + 9995.

It is an arithmetic number, because the mean of its divisors is an integer number (104622).

2⁶³⁷⁶⁶⁴ is an apocalyptic number.

It is an amenable number.

637664 is a deficient number, since it is larger than the sum of its proper divisors (617800).

637664 is a wasteful number, since it uses less digits than its factorization.

637664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19937 (or 19929 counting only the distinct ones).

The product of its digits is 18144, while the sum is 32.

The square root of 637664 is about 798.5386653131. The cubic root of 637664 is about 86.0724106206.

The spelling of 637664 in words is "six hundred thirty-seven thousand, six hundred sixty-four".