138231397 has 2 divisors, whose sum is σ = 138231398. Its totient is φ = 138231396.

The previous prime is 138231349. The next prime is 138231421. The reversal of 138231397 is 793132831.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 134235396 + 3996001 = 11586^2 + 1999^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-138231397 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138231347) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69115698 + 69115699.

It is an arithmetic number, because the mean of its divisors is an integer number (69115699).

Almost surely, 2^138231397 is an apocalyptic number.

It is an amenable number.

138231397 is a deficient number, since it is larger than the sum of its proper divisors (1).

138231397 is an equidigital number, since it uses as much as digits as its factorization.

138231397 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27216, while the sum is 37.

The square root of 138231397 is about 11757.1849096627. The cubic root of 138231397 is about 517.0535993425.

The spelling of 138231397 in words is "one hundred thirty-eight million, two hundred thirty-one thousand, three hundred ninety-seven".