638188432 has 80 divisors (see below), whose sum is σ = 1536865920. Its totient is φ = 250435584.

The previous prime is 638188417. The next prime is 638188451. The reversal of 638188432 is 234881836.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 65919 + ... + 74977.

It is an arithmetic number, because the mean of its divisors is an integer number (19210824).

Almost surely, 2^638188432 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 638188432, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (768432960).

638188432 is an abundant number, since it is smaller than the sum of its proper divisors (898677488).

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

638188432 is a wasteful number, since it uses less digits than its factorization.

638188432 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9128 (or 9122 counting only the distinct ones).

The product of its digits is 221184, while the sum is 43.

The square root of 638188432 is about 25262.3916524149. The cubic root of 638188432 is about 860.9600024226.

The spelling of 638188432 in words is "six hundred thirty-eight million, one hundred eighty-eight thousand, four hundred thirty-two".