638634132 has 72 divisors (see below), whose sum is σ = 1701717472. Its totient is φ = 209368800.

The previous prime is 638634089. The next prime is 638634173. The reversal of 638634132 is 231436836.

638634132 is a `hidden beast` number, since 6 + 3 + 8 + 634 + 13 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

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, 53907 + ... + 64677.

Almost surely, 2^638634132 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 638634132, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (850858736).

638634132 is an abundant number, since it is smaller than the sum of its proper divisors (1063083340).

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

638634132 is a wasteful number, since it uses less digits than its factorization.

638634132 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10851 (or 10837 counting only the distinct ones).

The product of its digits is 62208, while the sum is 36.

The square root of 638634132 is about 25271.2115261615. The cubic root of 638634132 is about 861.1603824140.

The spelling of 638634132 in words is "six hundred thirty-eight million, six hundred thirty-four thousand, one hundred thirty-two".