664843460557 has 2 divisors, whose sum is σ = 664843460558. Its totient is φ = 664843460556.

The previous prime is 664843460551. The next prime is 664843460669. The reversal of 664843460557 is 755064348466.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 523222202281 + 141621258276 = 723341^2 + 376326^2 .

It is a cyclic number.

It is not a de Polignac number, because 664843460557 - 2⁷ = 664843460429 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (664843460551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332421730278 + 332421730279.

It is an arithmetic number, because the mean of its divisors is an integer number (332421730279).

Almost surely, 2^664843460557 is an apocalyptic number.

It is an amenable number.

664843460557 is a deficient number, since it is larger than the sum of its proper divisors (1).

664843460557 is an equidigital number, since it uses as much as digits as its factorization.

664843460557 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 58060800, while the sum is 58.

The spelling of 664843460557 in words is "six hundred sixty-four billion, eight hundred forty-three million, four hundred sixty thousand, five hundred fifty-seven".