666536635717 has 2 divisors, whose sum is σ = 666536635718. Its totient is φ = 666536635716.

The previous prime is 666536635649. The next prime is 666536635727. The reversal of 666536635717 is 717536635666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 622207017601 + 44329618116 = 788801^2 + 210546^2 .

It is a cyclic number.

It is not a de Polignac number, because 666536635717 - 2¹¹ = 666536633669 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (666536635727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333268317858 + 333268317859.

It is an arithmetic number, because the mean of its divisors is an integer number (333268317859).

Almost surely, 2^666536635717 is an apocalyptic number.

It is an amenable number.

666536635717 is a deficient number, since it is larger than the sum of its proper divisors (1).

666536635717 is an equidigital number, since it uses as much as digits as its factorization.

666536635717 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 85730400, while the sum is 61.

The spelling of 666536635717 in words is "six hundred sixty-six billion, five hundred thirty-six million, six hundred thirty-five thousand, seven hundred seventeen".