138836491 has 2 divisors, whose sum is σ = 138836492. Its totient is φ = 138836490.

The previous prime is 138836483. The next prime is 138836539. The reversal of 138836491 is 194638831.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 138836491 - 2³ = 138836483 is a prime.

It is not a weakly prime, because it can be changed into another prime (138336491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69418245 + 69418246.

It is an arithmetic number, because the mean of its divisors is an integer number (69418246).

Almost surely, 2^138836491 is an apocalyptic number.

138836491 is a deficient number, since it is larger than the sum of its proper divisors (1).

138836491 is an equidigital number, since it uses as much as digits as its factorization.

138836491 is an evil number, because the sum of its binary digits is even.

The product of its digits is 124416, while the sum is 43.

The square root of 138836491 is about 11782.8897559130. The cubic root of 138836491 is about 517.8069511647.

The spelling of 138836491 in words is "one hundred thirty-eight million, eight hundred thirty-six thousand, four hundred ninety-one".