138879449 has 2 divisors, whose sum is σ = 138879450. Its totient is φ = 138879448.

The previous prime is 138879413. The next prime is 138879523. The reversal of 138879449 is 944978831.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 128414224 + 10465225 = 11332^2 + 3235^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-138879449 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 138879449.

It is not a weakly prime, because it can be changed into another prime (138879649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69439724 + 69439725.

It is an arithmetic number, because the mean of its divisors is an integer number (69439725).

Almost surely, 2^138879449 is an apocalyptic number.

It is an amenable number.

138879449 is a deficient number, since it is larger than the sum of its proper divisors (1).

138879449 is an equidigital number, since it uses as much as digits as its factorization.

138879449 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1741824, while the sum is 53.

The square root of 138879449 is about 11784.7125124035. The cubic root of 138879449 is about 517.8603512880.

The spelling of 138879449 in words is "one hundred thirty-eight million, eight hundred seventy-nine thousand, four hundred forty-nine".