638844832626 has 256 divisors, whose sum is σ = 1727966822400. Its totient is φ = 152061235200.

The previous prime is 638844832589. The next prime is 638844832729. The reversal of 638844832626 is 626238448836.

It is a self number, because there is not a number n which added to its sum of digits gives 638844832626.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 633146010 + ... + 633147018.

It is an arithmetic number, because the mean of its divisors is an integer number (6749870400).

Almost surely, 2^638844832626 is an apocalyptic number.

638844832626 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 638844832626, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (863983411200).

638844832626 is an abundant number, since it is smaller than the sum of its proper divisors (1089121989774).

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

638844832626 is a wasteful number, since it uses less digits than its factorization.

638844832626 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1705.

The product of its digits is 63700992, while the sum is 60.

It can be divided in two parts, 638844 and 832626, that added together give a triangular number (1471470 = T₁₇₁₅).

The spelling of 638844832626 in words is "six hundred thirty-eight billion, eight hundred forty-four million, eight hundred thirty-two thousand, six hundred twenty-six".