138806431 has 2 divisors, whose sum is σ = 138806432. Its totient is φ = 138806430.

The previous prime is 138806429. The next prime is 138806467. The reversal of 138806431 is 134608831.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 138806431 - 2¹ = 138806429 is a prime.

It is a super-2 number, since 2×138806431² = 38534450573915522, which contains 22 as substring.

Together with 138806429, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138806231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69403215 + 69403216.

It is an arithmetic number, because the mean of its divisors is an integer number (69403216).

Almost surely, 2^138806431 is an apocalyptic number.

138806431 is a deficient number, since it is larger than the sum of its proper divisors (1).

138806431 is an equidigital number, since it uses as much as digits as its factorization.

138806431 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13824, while the sum is 34.

The square root of 138806431 is about 11781.6141084318. The cubic root of 138806431 is about 517.7695777039.

The spelling of 138806431 in words is "one hundred thirty-eight million, eight hundred six thousand, four hundred thirty-one".