138538879 has 2 divisors, whose sum is σ = 138538880. Its totient is φ = 138538878.

The previous prime is 138538853. The next prime is 138538909. The reversal of 138538879 is 978835831.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 138538879 - 2¹⁵ = 138506111 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138568879) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69269439 + 69269440.

It is an arithmetic number, because the mean of its divisors is an integer number (69269440).

Almost surely, 2^138538879 is an apocalyptic number.

138538879 is a deficient number, since it is larger than the sum of its proper divisors (1).

138538879 is an equidigital number, since it uses as much as digits as its factorization.

138538879 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1451520, while the sum is 52.

The square root of 138538879 is about 11770.2539904626. The cubic root of 138538879 is about 517.4366935403.

The spelling of 138538879 in words is "one hundred thirty-eight million, five hundred thirty-eight thousand, eight hundred seventy-nine".