138317498635721 has 2 divisors, whose sum is σ = 138317498635722. Its totient is φ = 138317498635720.

The previous prime is 138317498635633. The next prime is 138317498635733. The reversal of 138317498635721 is 127536894713831.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 138235608228496 + 81890407225 = 11757364^2 + 286165^2 .

It is a cyclic number.

It is not a de Polignac number, because 138317498635721 - 2³⁴ = 138300318766537 is a prime.

It is not a weakly prime, because it can be changed into another prime (138317498635621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69158749317860 + 69158749317861.

It is an arithmetic number, because the mean of its divisors is an integer number (69158749317861).

Almost surely, 2^{138317498635721} is an apocalyptic number.

It is an amenable number.

138317498635721 is a deficient number, since it is larger than the sum of its proper divisors (1).

138317498635721 is an equidigital number, since it uses as much as digits as its factorization.

138317498635721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 182891520, while the sum is 68.

The spelling of 138317498635721 in words is "one hundred thirty-eight trillion, three hundred seventeen billion, four hundred ninety-eight million, six hundred thirty-five thousand, seven hundred twenty-one".