638821778124 has 48 divisors (see below), whose sum is σ = 1493846575200. Its totient is φ = 212475041280.

The previous prime is 638821778087. The next prime is 638821778149. The reversal of 638821778124 is 421877128836.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10303842 + ... + 10365654.

It is an arithmetic number, because the mean of its divisors is an integer number (31121803650).

Almost surely, 2^638821778124 is an apocalyptic number.

It is an amenable number.

638821778124 is an abundant number, since it is smaller than the sum of its proper divisors (855024797076).

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

638821778124 is a wasteful number, since it uses less digits than its factorization.

638821778124 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63690 (or 63688 counting only the distinct ones).

The product of its digits is 7225344, while the sum is 57.

The spelling of 638821778124 in words is "six hundred thirty-eight billion, eight hundred twenty-one million, seven hundred seventy-eight thousand, one hundred twenty-four".