638633022372 has 72 divisors (see below), whose sum is σ = 1658564454456. Its totient is φ = 207047798784.

The previous prime is 638633022359. The next prime is 638633022407. The reversal of 638633022372 is 273220336836.

638633022372 is a `hidden beast` number, since 6 + 3 + 8 + 633 + 0 + 2 + 2 + 3 + 7 + 2 = 666.

638633022372 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 273713126976 + 364919895396 = 523176^2 + 604086^2 .

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, 3579918 + ... + 3754074.

It is an arithmetic number, because the mean of its divisors is an integer number (23035617423).

Almost surely, 2^638633022372 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 638633022372, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (829282227228).

638633022372 is an abundant number, since it is smaller than the sum of its proper divisors (1019931432084).

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

638633022372 is a wasteful number, since it uses less digits than its factorization.

638633022372 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 176957 (or 176952 counting only the distinct ones).

The product of its (nonzero) digits is 1306368, while the sum is 45.

The spelling of 638633022372 in words is "six hundred thirty-eight billion, six hundred thirty-three million, twenty-two thousand, three hundred seventy-two".