138751387561 has 2 divisors, whose sum is σ = 138751387562. Its totient is φ = 138751387560.

The previous prime is 138751387549. The next prime is 138751387589. The reversal of 138751387561 is 165783157831.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 133129387161 + 5622000400 = 364869^2 + 74980^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-138751387561 is a prime.

It is not a weakly prime, because it can be changed into another prime (138751388561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69375693780 + 69375693781.

It is an arithmetic number, because the mean of its divisors is an integer number (69375693781).

Almost surely, 2^138751387561 is an apocalyptic number.

It is an amenable number.

138751387561 is a deficient number, since it is larger than the sum of its proper divisors (1).

138751387561 is an equidigital number, since it uses as much as digits as its factorization.

138751387561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4233600, while the sum is 55.

The spelling of 138751387561 in words is "one hundred thirty-eight billion, seven hundred fifty-one million, three hundred eighty-seven thousand, five hundred sixty-one".