638844675228 has 72 divisors (see below), whose sum is σ = 1672107746400. Its totient is φ = 205412489856.

The previous prime is 638844675193. The next prime is 638844675263. The reversal of 638844675228 is 822576448836.

638844675228 is a `hidden beast` number, since 6 + 3 + 8 + 8 + 44 + 67 + 522 + 8 = 666.

It is an interprime number because it is at equal distance from previous prime (638844675193) and next prime (638844675263).

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, 829825 + ... + 1402247.

It is an arithmetic number, because the mean of its divisors is an integer number (23223718700).

Almost surely, 2^638844675228 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 638844675228, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (836053873200).

638844675228 is an abundant number, since it is smaller than the sum of its proper divisors (1033263071172).

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

638844675228 is a wasteful number, since it uses less digits than its factorization.

638844675228 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 573531 (or 573526 counting only the distinct ones).

The product of its digits is 123863040, while the sum is 63.

The spelling of 638844675228 in words is "six hundred thirty-eight billion, eight hundred forty-four million, six hundred seventy-five thousand, two hundred twenty-eight".