638672 has 20 divisors (see below), whose sum is σ = 1249920. Its totient is φ = 316128.

The previous prime is 638669. The next prime is 638689. The reversal of 638672 is 276836.

It is a Smith number, since the sum of its digits (32) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2753 + ... + 2975.

It is an arithmetic number, because the mean of its divisors is an integer number (62496).

2⁶³⁸⁶⁷² is an apocalyptic number.

It is an amenable number.

638672 is a deficient number, since it is larger than the sum of its proper divisors (611248).

638672 is a wasteful number, since it uses less digits than its factorization.

638672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 410 (or 404 counting only the distinct ones).

The product of its digits is 12096, while the sum is 32.

The square root of 638672 is about 799.1695689902. The cubic root of 638672 is about 86.1177402998.

The spelling of 638672 in words is "six hundred thirty-eight thousand, six hundred seventy-two".