665613717995519 has 2 divisors, whose sum is σ = 665613717995520. Its totient is φ = 665613717995518.

The previous prime is 665613717995509. The next prime is 665613717995557. The reversal of 665613717995519 is 915599717316566.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 665613717995519 - 2²⁴ = 665613701218303 is a prime.

It is a super-2 number, since 2×665613717995519² (a number of 30 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (665613717995509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332806858997759 + 332806858997760.

It is an arithmetic number, because the mean of its divisors is an integer number (332806858997760).

Almost surely, 2^{665613717995519} is an apocalyptic number.

665613717995519 is a deficient number, since it is larger than the sum of its proper divisors (1).

665613717995519 is an equidigital number, since it uses as much as digits as its factorization.

665613717995519 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2893401000, while the sum is 80.

The spelling of 665613717995519 in words is "six hundred sixty-five trillion, six hundred thirteen billion, seven hundred seventeen million, nine hundred ninety-five thousand, five hundred nineteen".