638172 has 48 divisors (see below), whose sum is σ = 1747200. Its totient is φ = 200880.

The previous prime is 638171. The next prime is 638177. The reversal of 638172 is 271836.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638171) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1897 + ... + 2207.

It is an arithmetic number, because the mean of its divisors is an integer number (36400).

2⁶³⁸¹⁷² 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 638172, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (873600).

638172 is an abundant number, since it is smaller than the sum of its proper divisors (1109028).

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

638172 is a wasteful number, since it uses less digits than its factorization.

638172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 343 (or 335 counting only the distinct ones).

The product of its digits is 2016, while the sum is 27.

The square root of 638172 is about 798.8566830164. The cubic root of 638172 is about 86.0952613061.

The spelling of 638172 in words is "six hundred thirty-eight thousand, one hundred seventy-two".