138728668517 has 2 divisors, whose sum is σ = 138728668518. Its totient is φ = 138728668516.

The previous prime is 138728668513. The next prime is 138728668537. The reversal of 138728668517 is 715866827831.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 123739318756 + 14989349761 = 351766^2 + 122431^2 .

It is a cyclic number.

It is not a de Polignac number, because 138728668517 - 2² = 138728668513 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 138728668517.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138728668513) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69364334258 + 69364334259.

It is an arithmetic number, because the mean of its divisors is an integer number (69364334259).

Almost surely, 2^138728668517 is an apocalyptic number.

It is an amenable number.

138728668517 is a deficient number, since it is larger than the sum of its proper divisors (1).

138728668517 is an equidigital number, since it uses as much as digits as its factorization.

138728668517 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27095040, while the sum is 62.

The spelling of 138728668517 in words is "one hundred thirty-eight billion, seven hundred twenty-eight million, six hundred sixty-eight thousand, five hundred seventeen".