638108819136 has 560 divisors, whose sum is σ = 2031394464000. Its totient is φ = 197615738880.

The previous prime is 638108819083. The next prime is 638108819207. The reversal of 638108819136 is 631918801836.

638108819136 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 1253651650 + ... + 1253652158.

Almost surely, 2^638108819136 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 638108819136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1015697232000).

638108819136 is an abundant number, since it is smaller than the sum of its proper divisors (1393285644864).

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

638108819136 is a wasteful number, since it uses less digits than its factorization.

638108819136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 862 (or 843 counting only the distinct ones).

The product of its (nonzero) digits is 1492992, while the sum is 54.

The spelling of 638108819136 in words is "six hundred thirty-eight billion, one hundred eight million, eight hundred nineteen thousand, one hundred thirty-six".