138556979 has 6 divisors (see below), whose sum is σ = 152298300. Its totient is φ = 125960780.

The previous prime is 138556973. The next prime is 138556981. The reversal of 138556979 is 979655831.

It is a de Polignac number, because none of the positive numbers 2^k-138556979 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 138556979.

It is not an unprimeable number, because it can be changed into a prime (138556973) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 572429 + ... + 572670.

It is an arithmetic number, because the mean of its divisors is an integer number (25383050).

Almost surely, 2^138556979 is an apocalyptic number.

138556979 is a deficient number, since it is larger than the sum of its proper divisors (13741321).

138556979 is a wasteful number, since it uses less digits than its factorization.

138556979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1145121 (or 1145110 counting only the distinct ones).

The product of its digits is 2041200, while the sum is 53.

The square root of 138556979 is about 11771.0228527516. The cubic root of 138556979 is about 517.4592267969.

The spelling of 138556979 in words is "one hundred thirty-eight million, five hundred fifty-six thousand, nine hundred seventy-nine".