638819532 has 72 divisors (see below), whose sum is σ = 1755398736. Its totient is φ = 194707584.

The previous prime is 638819527. The next prime is 638819561. The reversal of 638819532 is 235918836.

It is a happy number.

638819532 is a `hidden beast` number, since 6 + 38 + 81 + 9 + 532 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 43698 + ... + 56454.

It is an arithmetic number, because the mean of its divisors is an integer number (24380538).

Almost surely, 2^638819532 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 638819532, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (877699368).

638819532 is an abundant number, since it is smaller than the sum of its proper divisors (1116579204).

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

638819532 is a wasteful number, since it uses less digits than its factorization.

638819532 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12887 (or 12882 counting only the distinct ones).

The product of its digits is 311040, while the sum is 45.

The square root of 638819532 is about 25274.8794655880. The cubic root of 638819532 is about 861.2437079987.

The spelling of 638819532 in words is "six hundred thirty-eight million, eight hundred nineteen thousand, five hundred thirty-two".