666222116321 has 2 divisors, whose sum is σ = 666222116322. Its totient is φ = 666222116320.

The previous prime is 666222116317. The next prime is 666222116363. The reversal of 666222116321 is 123611222666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 339701299921 + 326520816400 = 582839^2 + 571420^2 .

It is a cyclic number.

It is not a de Polignac number, because 666222116321 - 2² = 666222116317 is a prime.

It is not a weakly prime, because it can be changed into another prime (666222116921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333111058160 + 333111058161.

It is an arithmetic number, because the mean of its divisors is an integer number (333111058161).

Almost surely, 2^666222116321 is an apocalyptic number.

It is an amenable number.

666222116321 is a deficient number, since it is larger than the sum of its proper divisors (1).

666222116321 is an equidigital number, since it uses as much as digits as its factorization.

666222116321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 62208, while the sum is 38.

Adding to 666222116321 its reverse (123611222666), we get a palindrome (789833338987).

The spelling of 666222116321 in words is "six hundred sixty-six billion, two hundred twenty-two million, one hundred sixteen thousand, three hundred twenty-one".