638213632 has 60 divisors (see below), whose sum is σ = 1483431840. Its totient is φ = 273509376.

The previous prime is 638213603. The next prime is 638213789. The reversal of 638213632 is 236312836.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 12369 + ... + 37807.

It is an arithmetic number, because the mean of its divisors is an integer number (24723864).

Almost surely, 2^638213632 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 638213632, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (741715920).

638213632 is an abundant number, since it is smaller than the sum of its proper divisors (845218208).

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

638213632 is an equidigital number, since it uses as much as digits as its factorization.

638213632 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25471 (or 25448 counting only the distinct ones).

The product of its digits is 31104, while the sum is 34.

The square root of 638213632 is about 25262.8904126191. The cubic root of 638213632 is about 860.9713344501.

The spelling of 638213632 in words is "six hundred thirty-eight million, two hundred thirteen thousand, six hundred thirty-two".