664864493 has 2 divisors, whose sum is σ = 664864494. Its totient is φ = 664864492.

The previous prime is 664864477. The next prime is 664864513. The reversal of 664864493 is 394468466.

It is a happy number.

664864493 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 335732329 + 329132164 = 18323^2 + 18142^2 .

It is a cyclic number.

It is not a de Polignac number, because 664864493 - 2⁴ = 664864477 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (664864423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332432246 + 332432247.

It is an arithmetic number, because the mean of its divisors is an integer number (332432247).

Almost surely, 2^664864493 is an apocalyptic number.

It is an amenable number.

664864493 is a deficient number, since it is larger than the sum of its proper divisors (1).

664864493 is an equidigital number, since it uses as much as digits as its factorization.

664864493 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2985984, while the sum is 50.

The square root of 664864493 is about 25784.9664145602. The cubic root of 664864493 is about 872.7925825043.

The spelling of 664864493 in words is "six hundred sixty-four million, eight hundred sixty-four thousand, four hundred ninety-three".