638887139 has 24 divisors (see below), whose sum is σ = 731574480. Its totient is φ = 556839360.

The previous prime is 638887127. The next prime is 638887157. The reversal of 638887139 is 931788836.

It is not a de Polignac number, because 638887139 - 2¹² = 638883043 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638887159) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 571409 + ... + 572525.

It is an arithmetic number, because the mean of its divisors is an integer number (30482270).

Almost surely, 2^638887139 is an apocalyptic number.

638887139 is a deficient number, since it is larger than the sum of its proper divisors (92687341).

638887139 is a wasteful number, since it uses less digits than its factorization.

638887139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1331 (or 1320 counting only the distinct ones).

The product of its digits is 1741824, while the sum is 53.

The square root of 638887139 is about 25276.2168648712. The cubic root of 638887139 is about 861.2740890617.

The spelling of 638887139 in words is "six hundred thirty-eight million, eight hundred eighty-seven thousand, one hundred thirty-nine".