666778596053 has 2 divisors, whose sum is σ = 666778596054. Its totient is φ = 666778596052.

The previous prime is 666778596041. The next prime is 666778596131. The reversal of 666778596053 is 350695877666.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 663276678724 + 3501917329 = 814418^2 + 59177^2 .

It is a cyclic number.

It is not a de Polignac number, because 666778596053 - 2¹⁰ = 666778595029 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (666778566053) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333389298026 + 333389298027.

It is an arithmetic number, because the mean of its divisors is an integer number (333389298027).

Almost surely, 2^666778596053 is an apocalyptic number.

It is an amenable number.

666778596053 is a deficient number, since it is larger than the sum of its proper divisors (1).

666778596053 is an equidigital number, since it uses as much as digits as its factorization.

666778596053 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 342921600, while the sum is 68.

The spelling of 666778596053 in words is "six hundred sixty-six billion, seven hundred seventy-eight million, five hundred ninety-six thousand, fifty-three".