138464639 has 2 divisors, whose sum is σ = 138464640. Its totient is φ = 138464638.

The previous prime is 138464597. The next prime is 138464659. The reversal of 138464639 is 936464831.

138464639 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 138464639 - 2²⁰ = 137416063 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 138464639.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138464659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69232319 + 69232320.

It is an arithmetic number, because the mean of its divisors is an integer number (69232320).

Almost surely, 2^138464639 is an apocalyptic number.

138464639 is a deficient number, since it is larger than the sum of its proper divisors (1).

138464639 is an equidigital number, since it uses as much as digits as its factorization.

138464639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 373248, while the sum is 44.

The square root of 138464639 is about 11767.0998551045. The cubic root of 138464639 is about 517.3442493006.

The spelling of 138464639 in words is "one hundred thirty-eight million, four hundred sixty-four thousand, six hundred thirty-nine".