666594618691 has 2 divisors, whose sum is σ = 666594618692. Its totient is φ = 666594618690.

The previous prime is 666594618689. The next prime is 666594618769. The reversal of 666594618691 is 196816495666.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 666594618691 - 2¹ = 666594618689 is a prime.

Together with 666594618689, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (666594618631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333297309345 + 333297309346.

It is an arithmetic number, because the mean of its divisors is an integer number (333297309346).

Almost surely, 2^666594618691 is an apocalyptic number.

666594618691 is a deficient number, since it is larger than the sum of its proper divisors (1).

666594618691 is an equidigital number, since it uses as much as digits as its factorization.

666594618691 is an evil number, because the sum of its binary digits is even.

The product of its digits is 100776960, while the sum is 67.

The spelling of 666594618691 in words is "six hundred sixty-six billion, five hundred ninety-four million, six hundred eighteen thousand, six hundred ninety-one".