138581791 has 2 divisors, whose sum is σ = 138581792. Its totient is φ = 138581790.

The previous prime is 138581759. The next prime is 138581827. The reversal of 138581791 is 197185831.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 138581791 - 2⁵ = 138581759 is a prime.

It is equal to p_7836496 and since 138581791 and 7836496 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 (138581711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69290895 + 69290896.

It is an arithmetic number, because the mean of its divisors is an integer number (69290896).

Almost surely, 2^138581791 is an apocalyptic number.

138581791 is a deficient number, since it is larger than the sum of its proper divisors (1).

138581791 is an equidigital number, since it uses as much as digits as its factorization.

138581791 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 60480, while the sum is 43.

The square root of 138581791 is about 11772.0767496649. The cubic root of 138581791 is about 517.4901128437.

The spelling of 138581791 in words is "one hundred thirty-eight million, five hundred eighty-one thousand, seven hundred ninety-one".