665563661597 has 2 divisors, whose sum is σ = 665563661598. Its totient is φ = 665563661596.

The previous prime is 665563661561. The next prime is 665563661603. The reversal of 665563661597 is 795166365566.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 665519850436 + 43811161 = 815794^2 + 6619^2 .

It is a cyclic number.

It is not a de Polignac number, because 665563661597 - 2¹⁴ = 665563645213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (665563661507) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332781830798 + 332781830799.

It is an arithmetic number, because the mean of its divisors is an integer number (332781830799).

Almost surely, 2^665563661597 is an apocalyptic number.

It is an amenable number.

665563661597 is a deficient number, since it is larger than the sum of its proper divisors (1).

665563661597 is an equidigital number, since it uses as much as digits as its factorization.

665563661597 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 183708000, while the sum is 65.

The spelling of 665563661597 in words is "six hundred sixty-five billion, five hundred sixty-three million, six hundred sixty-one thousand, five hundred ninety-seven".