638626380 has 48 divisors (see below), whose sum is σ = 2043605760. Its totient is φ = 145971648.

The previous prime is 638626363. The next prime is 638626399. The reversal of 638626380 is 83626836.

It is a hoax number, since the sum of its digits (42) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 759850 + ... + 760689.

It is an arithmetic number, because the mean of its divisors is an integer number (42575120).

Almost surely, 2^638626380 is an apocalyptic number.

638626380 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

638626380 is an abundant number, since it is smaller than the sum of its proper divisors (1404979380).

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

638626380 is a wasteful number, since it uses less digits than its factorization.

638626380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1520558 (or 1520556 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 42.

The square root of 638626380 is about 25271.0581495908. The cubic root of 638626380 is about 861.1568980286.

The spelling of 638626380 in words is "six hundred thirty-eight million, six hundred twenty-six thousand, three hundred eighty".