138492391 has 2 divisors, whose sum is σ = 138492392. Its totient is φ = 138492390.

The previous prime is 138492377. The next prime is 138492397. The reversal of 138492391 is 193294831.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 138492391 - 2⁹ = 138491879 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138492397) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69246195 + 69246196.

It is an arithmetic number, because the mean of its divisors is an integer number (69246196).

Almost surely, 2^138492391 is an apocalyptic number.

138492391 is a deficient number, since it is larger than the sum of its proper divisors (1).

138492391 is an equidigital number, since it uses as much as digits as its factorization.

138492391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 46656, while the sum is 40.

The square root of 138492391 is about 11768.2790160669. The cubic root of 138492391 is about 517.3788101787.

The spelling of 138492391 in words is "one hundred thirty-eight million, four hundred ninety-two thousand, three hundred ninety-one".