666631305121 has 2 divisors, whose sum is σ = 666631305122. Its totient is φ = 666631305120.

The previous prime is 666631305089. The next prime is 666631305139. The reversal of 666631305121 is 121503136666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 647188070400 + 19443234721 = 804480^2 + 139439^2 .

It is a cyclic number.

It is not a de Polignac number, because 666631305121 - 2⁵ = 666631305089 is a prime.

It is not a weakly prime, because it can be changed into another prime (666631305161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333315652560 + 333315652561.

It is an arithmetic number, because the mean of its divisors is an integer number (333315652561).

Almost surely, 2^666631305121 is an apocalyptic number.

It is an amenable number.

666631305121 is a deficient number, since it is larger than the sum of its proper divisors (1).

666631305121 is an equidigital number, since it uses as much as digits as its factorization.

666631305121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 116640, while the sum is 40.

The spelling of 666631305121 in words is "six hundred sixty-six billion, six hundred thirty-one million, three hundred five thousand, one hundred twenty-one".