138686579 has 4 divisors (see below), whose sum is σ = 138710184. Its totient is φ = 138662976.

The previous prime is 138686563. The next prime is 138686593. The reversal of 138686579 is 975686831.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 138686579 - 2⁴ = 138686563 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 138686579.

It is not an unprimeable number, because it can be changed into a prime (138686539) 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, 4739 + ... + 17315.

It is an arithmetic number, because the mean of its divisors is an integer number (34677546).

Almost surely, 2^138686579 is an apocalyptic number.

138686579 is a deficient number, since it is larger than the sum of its proper divisors (23605).

138686579 is a wasteful number, since it uses less digits than its factorization.

138686579 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23604.

The product of its digits is 2177280, while the sum is 53.

The square root of 138686579 is about 11776.5266101682. The cubic root of 138686579 is about 517.6205125918.

The spelling of 138686579 in words is "one hundred thirty-eight million, six hundred eighty-six thousand, five hundred seventy-nine".