138639443 has 2 divisors, whose sum is σ = 138639444. Its totient is φ = 138639442.

The previous prime is 138639419. The next prime is 138639493. The reversal of 138639443 is 344936831.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 138639443 - 2⁸ = 138639187 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 138639443.

It is not a weakly prime, because it can be changed into another prime (138639493) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69319721 + 69319722.

It is an arithmetic number, because the mean of its divisors is an integer number (69319722).

Almost surely, 2^138639443 is an apocalyptic number.

138639443 is a deficient number, since it is larger than the sum of its proper divisors (1).

138639443 is an equidigital number, since it uses as much as digits as its factorization.

138639443 is an evil number, because the sum of its binary digits is even.

The product of its digits is 186624, while the sum is 41.

The square root of 138639443 is about 11774.5251708933. The cubic root of 138639443 is about 517.5618639820.

The spelling of 138639443 in words is "one hundred thirty-eight million, six hundred thirty-nine thousand, four hundred forty-three".