638184671872 has 256 divisors, whose sum is σ = 1500556337280. Its totient is φ = 267100487680.

The previous prime is 638184671809. The next prime is 638184671893. The reversal of 638184671872 is 278176481836.

It is a self number, because there is not a number n which added to its sum of digits gives 638184671872.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 744672468 + ... + 744673324.

Almost surely, 2^638184671872 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 638184671872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (750278168640).

638184671872 is an abundant number, since it is smaller than the sum of its proper divisors (862371665408).

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

638184671872 is a wasteful number, since it uses less digits than its factorization.

638184671872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1539 (or 1527 counting only the distinct ones).

The product of its digits is 21676032, while the sum is 61.

The spelling of 638184671872 in words is "six hundred thirty-eight billion, one hundred eighty-four million, six hundred seventy-one thousand, eight hundred seventy-two".