638825688 has 96 divisors (see below), whose sum is σ = 1801753200. Its totient is φ = 204228864.

The previous prime is 638825687. The next prime is 638825743. The reversal of 638825688 is 886528836.

638825688 is a `hidden beast` number, since 6 + 388 + 256 + 8 + 8 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638825687) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 339406 + ... + 341282.

Almost surely, 2^638825688 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 638825688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (900876600).

638825688 is an abundant number, since it is smaller than the sum of its proper divisors (1162927512).

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

638825688 is a wasteful number, since it uses less digits than its factorization.

638825688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2081 (or 2074 counting only the distinct ones).

The product of its digits is 4423680, while the sum is 54.

The square root of 638825688 is about 25275.0012462908. The cubic root of 638825688 is about 861.2464744551.

The spelling of 638825688 in words is "six hundred thirty-eight million, eight hundred twenty-five thousand, six hundred eighty-eight".