666791959 has 2 divisors, whose sum is σ = 666791960. Its totient is φ = 666791958.

The previous prime is 666791953. The next prime is 666791963. The reversal of 666791959 is 959197666.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 666791959 - 2⁷ = 666791831 is a prime.

It is a super-2 number, since 2×666791959² = 889223033174115362, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (666791953) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333395979 + 333395980.

It is an arithmetic number, because the mean of its divisors is an integer number (333395980).

Almost surely, 2^666791959 is an apocalyptic number.

666791959 is a deficient number, since it is larger than the sum of its proper divisors (1).

666791959 is an equidigital number, since it uses as much as digits as its factorization.

666791959 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5511240, while the sum is 58.

The square root of 666791959 is about 25822.3151363312. The cubic root of 666791959 is about 873.6351877756.

The spelling of 666791959 in words is "six hundred sixty-six million, seven hundred ninety-one thousand, nine hundred fifty-nine".