664488581 has 2 divisors, whose sum is σ = 664488582. Its totient is φ = 664488580.

The previous prime is 664488553. The next prime is 664488619. The reversal of 664488581 is 185884466.

664488581 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., 344436481 + 320052100 = 18559^2 + 17890^2 .

It is a cyclic number.

It is not a de Polignac number, because 664488581 - 2²² = 660294277 is a prime.

It is a super-2 number, since 2×664488581² = 883090148558787122, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (664488521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332244290 + 332244291.

It is an arithmetic number, because the mean of its divisors is an integer number (332244291).

Almost surely, 2^664488581 is an apocalyptic number.

It is an amenable number.

664488581 is a deficient number, since it is larger than the sum of its proper divisors (1).

664488581 is an equidigital number, since it uses as much as digits as its factorization.

664488581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1474560, while the sum is 50.

The square root of 664488581 is about 25777.6760201536. The cubic root of 664488581 is about 872.6280602283.

The spelling of 664488581 in words is "six hundred sixty-four million, four hundred eighty-eight thousand, five hundred eighty-one".