664556897 has 2 divisors, whose sum is σ = 664556898. Its totient is φ = 664556896.

The previous prime is 664556839. The next prime is 664556933. The reversal of 664556897 is 798655466.

It is a happy number.

664556897 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 411237841 + 253319056 = 20279^2 + 15916^2 .

It is a cyclic number.

It is not a de Polignac number, because 664556897 - 2⁶ = 664556833 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (664576897) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332278448 + 332278449.

It is an arithmetic number, because the mean of its divisors is an integer number (332278449).

Almost surely, 2^664556897 is an apocalyptic number.

It is an amenable number.

664556897 is a deficient number, since it is larger than the sum of its proper divisors (1).

664556897 is an equidigital number, since it uses as much as digits as its factorization.

664556897 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10886400, while the sum is 56.

The square root of 664556897 is about 25779.0010861554. The cubic root of 664556897 is about 872.6579641360.

Subtracting from 664556897 its sum of digits (56), we obtain a square (664556841 = 25779²).

The spelling of 664556897 in words is "six hundred sixty-four million, five hundred fifty-six thousand, eight hundred ninety-seven".