638509891404 has 192 divisors, whose sum is σ = 1909370437632. Its totient is φ = 161221881600.

The previous prime is 638509891387. The next prime is 638509891447. The reversal of 638509891404 is 404198905836.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 41804289 + ... + 41819559.

It is an arithmetic number, because the mean of its divisors is an integer number (9944637696).

Almost surely, 2^638509891404 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 638509891404, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (954685218816).

638509891404 is an abundant number, since it is smaller than the sum of its proper divisors (1270860546228).

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

638509891404 is a wasteful number, since it uses less digits than its factorization.

638509891404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16556 (or 16554 counting only the distinct ones).

The product of its (nonzero) digits is 7464960, while the sum is 57.

The spelling of 638509891404 in words is "six hundred thirty-eight billion, five hundred nine million, eight hundred ninety-one thousand, four hundred four".