665684616089 has 2 divisors, whose sum is σ = 665684616090. Its totient is φ = 665684616088.

The previous prime is 665684616067. The next prime is 665684616127. The reversal of 665684616089 is 980616486566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 562440001600 + 103244614489 = 749960^2 + 321317^2 .

It is a cyclic number.

It is not a de Polignac number, because 665684616089 - 2²⁰ = 665683567513 is a prime.

It is not a weakly prime, because it can be changed into another prime (665684616059) 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, 332842308044 + 332842308045.

It is an arithmetic number, because the mean of its divisors is an integer number (332842308045).

Almost surely, 2^665684616089 is an apocalyptic number.

It is an amenable number.

665684616089 is a deficient number, since it is larger than the sum of its proper divisors (1).

665684616089 is an equidigital number, since it uses as much as digits as its factorization.

665684616089 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 89579520, while the sum is 65.

The spelling of 665684616089 in words is "six hundred sixty-five billion, six hundred eighty-four million, six hundred sixteen thousand, eighty-nine".