666530659591 has 2 divisors, whose sum is σ = 666530659592. Its totient is φ = 666530659590.

The previous prime is 666530659579. The next prime is 666530659609. The reversal of 666530659591 is 195956035666.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 666530659591 - 2⁷ = 666530659463 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (666530659891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333265329795 + 333265329796.

It is an arithmetic number, because the mean of its divisors is an integer number (333265329796).

Almost surely, 2^666530659591 is an apocalyptic number.

666530659591 is a deficient number, since it is larger than the sum of its proper divisors (1).

666530659591 is an equidigital number, since it uses as much as digits as its factorization.

666530659591 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 39366000, while the sum is 61.

The spelling of 666530659591 in words is "six hundred sixty-six billion, five hundred thirty million, six hundred fifty-nine thousand, five hundred ninety-one".