138731431 has 2 divisors, whose sum is σ = 138731432. Its totient is φ = 138731430.

The previous prime is 138731393. The next prime is 138731443. The reversal of 138731431 is 134137831.

It is a strong prime.

It is an emirp because it is prime and its reverse (134137831) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 138731431 - 2⁹ = 138730919 is a prime.

It is a super-2 number, since 2×138731431² = 38492819894615522, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 138731393 and 138731402.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138711431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69365715 + 69365716.

It is an arithmetic number, because the mean of its divisors is an integer number (69365716).

Almost surely, 2^138731431 is an apocalyptic number.

138731431 is a deficient number, since it is larger than the sum of its proper divisors (1).

138731431 is an equidigital number, since it uses as much as digits as its factorization.

138731431 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6048, while the sum is 31.

The square root of 138731431 is about 11778.4307528635. The cubic root of 138731431 is about 517.6763070147.

The spelling of 138731431 in words is "one hundred thirty-eight million, seven hundred thirty-one thousand, four hundred thirty-one".