638139 has 8 divisors (see below), whose sum is σ = 874000. Its totient is φ = 413856.

The previous prime is 638123. The next prime is 638147. The reversal of 638139 is 931836.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 638139 - 2⁴ = 638123 is a prime.

It is a Duffinian number.

638139 is a lucky number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 638139.

It is not an unprimeable number, because it can be changed into a prime (638159) 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 7 ways as a sum of consecutive naturals, for example, 2764 + ... + 2985.

It is an arithmetic number, because the mean of its divisors is an integer number (109250).

2⁶³⁸¹³⁹ is an apocalyptic number.

638139 is a deficient number, since it is larger than the sum of its proper divisors (235861).

638139 is a wasteful number, since it uses less digits than its factorization.

638139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5789.

The product of its digits is 3888, while the sum is 30.

The square root of 638139 is about 798.8360282311. The cubic root of 638139 is about 86.0937772795.

It can be divided in two parts, 638 and 139, that added together give a palindrome (777).

The spelling of 638139 in words is "six hundred thirty-eight thousand, one hundred thirty-nine".