138904789 has 2 divisors, whose sum is σ = 138904790. Its totient is φ = 138904788.

The previous prime is 138904783. The next prime is 138904793. The reversal of 138904789 is 987409831.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 137874564 + 1030225 = 11742^2 + 1015^2 .

It is an emirp because it is prime and its reverse (987409831) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 138904789 - 2⁵ = 138904757 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138904783) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69452394 + 69452395.

It is an arithmetic number, because the mean of its divisors is an integer number (69452395).

Almost surely, 2^138904789 is an apocalyptic number.

It is an amenable number.

138904789 is a deficient number, since it is larger than the sum of its proper divisors (1).

138904789 is an equidigital number, since it uses as much as digits as its factorization.

138904789 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 435456, while the sum is 49.

The square root of 138904789 is about 11785.7875850534. The cubic root of 138904789 is about 517.8918457084.

The spelling of 138904789 in words is "one hundred thirty-eight million, nine hundred four thousand, seven hundred eighty-nine".