669646541321 has 2 divisors, whose sum is σ = 669646541322. Its totient is φ = 669646541320.

The previous prime is 669646541279. The next prime is 669646541341. The reversal of 669646541321 is 123145646966.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 396547278400 + 273099262921 = 629720^2 + 522589^2 .

It is a cyclic number.

It is not a de Polignac number, because 669646541321 - 2³⁰ = 668572799497 is a prime.

It is not a weakly prime, because it can be changed into another prime (669646541341) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334823270660 + 334823270661.

It is an arithmetic number, because the mean of its divisors is an integer number (334823270661).

Almost surely, 2^669646541321 is an apocalyptic number.

It is an amenable number.

669646541321 is a deficient number, since it is larger than the sum of its proper divisors (1).

669646541321 is an equidigital number, since it uses as much as digits as its factorization.

669646541321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5598720, while the sum is 53.

The spelling of 669646541321 in words is "six hundred sixty-nine billion, six hundred forty-six million, five hundred forty-one thousand, three hundred twenty-one".