668055555569 has 2 divisors, whose sum is σ = 668055555570. Its totient is φ = 668055555568.

The previous prime is 668055555481. The next prime is 668055555613. The reversal of 668055555569 is 965555550866.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 434133396544 + 233922159025 = 658888^2 + 483655^2 .

It is a cyclic number.

It is not a de Polignac number, because 668055555569 - 2²⁸ = 667787120113 is a prime.

It is a super-2 number, since 2×668055555569² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (668055555269) 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, 334027777784 + 334027777785.

It is an arithmetic number, because the mean of its divisors is an integer number (334027777785).

Almost surely, 2^668055555569 is an apocalyptic number.

It is an amenable number.

668055555569 is a deficient number, since it is larger than the sum of its proper divisors (1).

668055555569 is an equidigital number, since it uses as much as digits as its factorization.

668055555569 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 243000000, while the sum is 65.

The spelling of 668055555569 in words is "six hundred sixty-eight billion, fifty-five million, five hundred fifty-five thousand, five hundred sixty-nine".