18639138638 has 8 divisors (see below), whose sum is σ = 27959295000. Its totient is φ = 9319373640.

The previous prime is 18639138629. The next prime is 18639138671. The reversal of 18639138638 is 83683193681.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 106988 + ... + 220736.

It is an arithmetic number, because the mean of its divisors is an integer number (3494911875).

Almost surely, 2^18639138638 is an apocalyptic number.

18639138638 is a deficient number, since it is larger than the sum of its proper divisors (9320156362).

18639138638 is a wasteful number, since it uses less digits than its factorization.

18639138638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195682.

The product of its digits is 4478976, while the sum is 56.

The spelling of 18639138638 in words is "eighteen billion, six hundred thirty-nine million, one hundred thirty-eight thousand, six hundred thirty-eight".