638904672 has 240 divisors, whose sum is σ = 2242259712. Its totient is φ = 174493440.

The previous prime is 638904671. The next prime is 638904709. The reversal of 638904672 is 276409836.

638904672 is a `hidden beast` number, since 638 + 9 + 0 + 4 + 6 + 7 + 2 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638904671) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 416547 + ... + 418077.

Almost surely, 2^638904672 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 638904672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1121129856).

638904672 is an abundant number, since it is smaller than the sum of its proper divisors (1603355040).

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

638904672 is a wasteful number, since it uses less digits than its factorization.

638904672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1583 (or 1566 counting only the distinct ones).

The product of its (nonzero) digits is 435456, while the sum is 45.

The square root of 638904672 is about 25276.5636905019. The cubic root of 638904672 is about 861.2819676470.

The spelling of 638904672 in words is "six hundred thirty-eight million, nine hundred four thousand, six hundred seventy-two".