138427391 has 2 divisors, whose sum is σ = 138427392. Its totient is φ = 138427390.

The previous prime is 138427349. The next prime is 138427417. The reversal of 138427391 is 193724831.

It is a strong prime.

It is an emirp because it is prime and its reverse (193724831) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 138427391 - 2⁶ = 138427327 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138427301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69213695 + 69213696.

It is an arithmetic number, because the mean of its divisors is an integer number (69213696).

Almost surely, 2^138427391 is an apocalyptic number.

138427391 is a deficient number, since it is larger than the sum of its proper divisors (1).

138427391 is an equidigital number, since it uses as much as digits as its factorization.

138427391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36288, while the sum is 38.

The square root of 138427391 is about 11765.5170307131. The cubic root of 138427391 is about 517.2978553454.

The spelling of 138427391 in words is "one hundred thirty-eight million, four hundred twenty-seven thousand, three hundred ninety-one".