666675648781217 has 2 divisors, whose sum is σ = 666675648781218. Its totient is φ = 666675648781216.

The previous prime is 666675648781199. The next prime is 666675648781237. The reversal of 666675648781217 is 712187846576666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 545243094894481 + 121432553886736 = 23350441^2 + 11019644^2 .

It is a cyclic number.

It is not a de Polignac number, because 666675648781217 - 2³² = 666671353813921 is a prime.

It is not a weakly prime, because it can be changed into another prime (666675648781237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333337824390608 + 333337824390609.

It is an arithmetic number, because the mean of its divisors is an integer number (333337824390609).

Almost surely, 2^{666675648781217} is an apocalyptic number.

It is an amenable number.

666675648781217 is a deficient number, since it is larger than the sum of its proper divisors (1).

666675648781217 is an equidigital number, since it uses as much as digits as its factorization.

666675648781217 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6827950080, while the sum is 80.

The spelling of 666675648781217 in words is "six hundred sixty-six trillion, six hundred seventy-five billion, six hundred forty-eight million, seven hundred eighty-one thousand, two hundred seventeen".