669405557 has 2 divisors, whose sum is σ = 669405558. Its totient is φ = 669405556.

The previous prime is 669405523. The next prime is 669405601. The reversal of 669405557 is 755504966.

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., 649281361 + 20124196 = 25481^2 + 4486^2 .

It is a cyclic number.

It is not a de Polignac number, because 669405557 - 2⁶ = 669405493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (669405257) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334702778 + 334702779.

It is an arithmetic number, because the mean of its divisors is an integer number (334702779).

Almost surely, 2^669405557 is an apocalyptic number.

It is an amenable number.

669405557 is a deficient number, since it is larger than the sum of its proper divisors (1).

669405557 is an equidigital number, since it uses as much as digits as its factorization.

669405557 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1134000, while the sum is 47.

The square root of 669405557 is about 25872.8729947024. The cubic root of 669405557 is about 874.7751507151.

The spelling of 669405557 in words is "six hundred sixty-nine million, four hundred five thousand, five hundred fifty-seven".