138624439 has 2 divisors, whose sum is σ = 138624440. Its totient is φ = 138624438.

The previous prime is 138624413. The next prime is 138624449. The reversal of 138624439 is 934426831.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-138624439 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138624449) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69312219 + 69312220.

It is an arithmetic number, because the mean of its divisors is an integer number (69312220).

Almost surely, 2^138624439 is an apocalyptic number.

138624439 is a deficient number, since it is larger than the sum of its proper divisors (1).

138624439 is an equidigital number, since it uses as much as digits as its factorization.

138624439 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 124416, while the sum is 40.

The square root of 138624439 is about 11773.8880154348. Note that the first 3 decimals coincide. The cubic root of 138624439 is about 517.5431925799.

The spelling of 138624439 in words is "one hundred thirty-eight million, six hundred twenty-four thousand, four hundred thirty-nine".