665168088509 has 2 divisors, whose sum is σ = 665168088510. Its totient is φ = 665168088508.

The previous prime is 665168088463. The next prime is 665168088547. The reversal of 665168088509 is 905880861566.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 604296343225 + 60871745284 = 777365^2 + 246722^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-665168088509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (665168081509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332584044254 + 332584044255.

It is an arithmetic number, because the mean of its divisors is an integer number (332584044255).

Almost surely, 2^665168088509 is an apocalyptic number.

It is an amenable number.

665168088509 is a deficient number, since it is larger than the sum of its proper divisors (1).

665168088509 is an equidigital number, since it uses as much as digits as its factorization.

665168088509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24883200, while the sum is 62.

The spelling of 665168088509 in words is "six hundred sixty-five billion, one hundred sixty-eight million, eighty-eight thousand, five hundred nine".