138638629 has 2 divisors, whose sum is σ = 138638630. Its totient is φ = 138638628.

The previous prime is 138638623. The next prime is 138638639. The reversal of 138638629 is 926836831.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 136072225 + 2566404 = 11665^2 + 1602^2 .

It is a cyclic number.

It is not a de Polignac number, because 138638629 - 2⁷ = 138638501 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 (138638623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69319314 + 69319315.

It is an arithmetic number, because the mean of its divisors is an integer number (69319315).

Almost surely, 2^138638629 is an apocalyptic number.

It is an amenable number.

138638629 is a deficient number, since it is larger than the sum of its proper divisors (1).

138638629 is an equidigital number, since it uses as much as digits as its factorization.

138638629 is an evil number, because the sum of its binary digits is even.

The product of its digits is 373248, while the sum is 46.

The square root of 138638629 is about 11774.4906046928. The cubic root of 138638629 is about 517.5608510520.

The spelling of 138638629 in words is "one hundred thirty-eight million, six hundred thirty-eight thousand, six hundred twenty-nine".