638138339 has 4 divisors (see below), whose sum is σ = 638230320. Its totient is φ = 638046360.

The previous prime is 638138329. The next prime is 638138341. The reversal of 638138339 is 933831836.

638138339 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 638138339 - 2⁴ = 638138323 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 638138339.

It is not an unprimeable number, because it can be changed into a prime (638138329) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34652 + ... + 49769.

It is an arithmetic number, because the mean of its divisors is an integer number (159557580).

Almost surely, 2^638138339 is an apocalyptic number.

638138339 is a deficient number, since it is larger than the sum of its proper divisors (91981).

638138339 is an equidigital number, since it uses as much as digits as its factorization.

638138339 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91980.

The product of its digits is 279936, while the sum is 44.

The square root of 638138339 is about 25261.4001789291. The cubic root of 638138339 is about 860.9374755347.

The spelling of 638138339 in words is "six hundred thirty-eight million, one hundred thirty-eight thousand, three hundred thirty-nine".