138442631 has 2 divisors, whose sum is σ = 138442632. Its totient is φ = 138442630.

The previous prime is 138442613. The next prime is 138442639. The reversal of 138442631 is 136244831.

Together with previous prime (138442613) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 138442631 - 2¹⁰ = 138441607 is a prime.

It is a super-2 number, since 2×138442631² = 38332724156404322, which contains 22 as substring.

It is a Sophie Germain prime.

It is equal to p_7829060 and since 138442631 and 7829060 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138442639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69221315 + 69221316.

It is an arithmetic number, because the mean of its divisors is an integer number (69221316).

Almost surely, 2^138442631 is an apocalyptic number.

138442631 is a deficient number, since it is larger than the sum of its proper divisors (1).

138442631 is an equidigital number, since it uses as much as digits as its factorization.

138442631 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13824, while the sum is 32.

The square root of 138442631 is about 11766.1646682341. The cubic root of 138442631 is about 517.3168384141.

The spelling of 138442631 in words is "one hundred thirty-eight million, four hundred forty-two thousand, six hundred thirty-one".