138908893 has 2 divisors, whose sum is σ = 138908894. Its totient is φ = 138908892.

The previous prime is 138908879. The next prime is 138908897. The reversal of 138908893 is 398809831.

138908893 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 can be written as a sum of positive squares in only one way, i.e., 137053849 + 1855044 = 11707^2 + 1362^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-138908893 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138908897) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69454446 + 69454447.

It is an arithmetic number, because the mean of its divisors is an integer number (69454447).

Almost surely, 2^138908893 is an apocalyptic number.

It is an amenable number.

138908893 is a deficient number, since it is larger than the sum of its proper divisors (1).

138908893 is an equidigital number, since it uses as much as digits as its factorization.

138908893 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 373248, while the sum is 49.

The square root of 138908893 is about 11785.9616917755. The cubic root of 138908893 is about 517.8969461018.

The spelling of 138908893 in words is "one hundred thirty-eight million, nine hundred eight thousand, eight hundred ninety-three".