138673979 has 2 divisors, whose sum is σ = 138673980. Its totient is φ = 138673978.

The previous prime is 138673963. The next prime is 138674009. The reversal of 138673979 is 979376831.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 138673979 - 2⁴ = 138673963 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 138673979.

It is not a weakly prime, because it can be changed into another prime (138673949) 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, 69336989 + 69336990.

It is an arithmetic number, because the mean of its divisors is an integer number (69336990).

Almost surely, 2^138673979 is an apocalyptic number.

138673979 is a deficient number, since it is larger than the sum of its proper divisors (1).

138673979 is an equidigital number, since it uses as much as digits as its factorization.

138673979 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1714608, while the sum is 53.

The square root of 138673979 is about 11775.9916355269. The cubic root of 138673979 is about 517.6048364391.

The spelling of 138673979 in words is "one hundred thirty-eight million, six hundred seventy-three thousand, nine hundred seventy-nine".