666778596131 has 2 divisors, whose sum is σ = 666778596132. Its totient is φ = 666778596130.

The previous prime is 666778596053. The next prime is 666778596157. The reversal of 666778596131 is 131695877666.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-666778596131 is a prime.

It is a super-2 number, since 2×666778596131² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (666778596191) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333389298065 + 333389298066.

It is an arithmetic number, because the mean of its divisors is an integer number (333389298066).

Almost surely, 2^666778596131 is an apocalyptic number.

666778596131 is a deficient number, since it is larger than the sum of its proper divisors (1).

666778596131 is an equidigital number, since it uses as much as digits as its factorization.

666778596131 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 68584320, while the sum is 65.

The spelling of 666778596131 in words is "six hundred sixty-six billion, seven hundred seventy-eight million, five hundred ninety-six thousand, one hundred thirty-one".