638621237992320 has 896 divisors, whose sum is σ = 2527187658710400. Its totient is φ = 152951899484160.

The previous prime is 638621237992307. The next prime is 638621237992369. The reversal of 638621237992320 is 23299732126836.

It is a happy number.

638621237992320 is a `hidden beast` number, since 6 + 3 + 8 + 6 + 21 + 2 + 379 + 9 + 232 + 0 = 666.

It is a super-2 number, since 2×638621237992320² (a number of 30 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 111 ways as a sum of consecutive naturals, for example, 425219671 + ... + 426718889.

It is an arithmetic number, because the mean of its divisors is an integer number (2820521940525).

Almost surely, 2^{638621237992320} is an apocalyptic number.

638621237992320 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638621237992320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1263593829355200).

638621237992320 is an abundant number, since it is smaller than the sum of its proper divisors (1888566420718080).

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

638621237992320 is a wasteful number, since it uses less digits than its factorization.

638621237992320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1499350 (or 1499323 counting only the distinct ones).

The product of its (nonzero) digits is 70543872, while the sum is 63.

The spelling of 638621237992320 in words is "six hundred thirty-eight trillion, six hundred twenty-one billion, two hundred thirty-seven million, nine hundred ninety-two thousand, three hundred twenty".