638677872 has 240 divisors, whose sum is σ = 2189637632. Its totient is φ = 176359680.

The previous prime is 638677859. The next prime is 638677883. The reversal of 638677872 is 278776836.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 843318 + ... + 844074.

Almost surely, 2^638677872 is an apocalyptic number.

638677872 is a gapful number since it is divisible by the number (62) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638677872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1094818816).

638677872 is an abundant number, since it is smaller than the sum of its proper divisors (1550959760).

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

638677872 is a wasteful number, since it uses less digits than its factorization.

638677872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 818 (or 800 counting only the distinct ones).

The product of its digits is 4741632, while the sum is 54.

The square root of 638677872 is about 25272.0769229599. The cubic root of 638677872 is about 861.1800422335.

The spelling of 638677872 in words is "six hundred thirty-eight million, six hundred seventy-seven thousand, eight hundred seventy-two".