664581347897 has 2 divisors, whose sum is σ = 664581347898. Its totient is φ = 664581347896.

The previous prime is 664581347849. The next prime is 664581347917. The reversal of 664581347897 is 798743185466.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 458811150736 + 205770197161 = 677356^2 + 453619^2 .

It is a cyclic number.

It is not a de Polignac number, because 664581347897 - 2¹⁰ = 664581346873 is a prime.

It is not a weakly prime, because it can be changed into another prime (664581347827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332290673948 + 332290673949.

It is an arithmetic number, because the mean of its divisors is an integer number (332290673949).

Almost surely, 2^664581347897 is an apocalyptic number.

It is an amenable number.

664581347897 is a deficient number, since it is larger than the sum of its proper divisors (1).

664581347897 is an equidigital number, since it uses as much as digits as its factorization.

664581347897 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 243855360, while the sum is 68.

The spelling of 664581347897 in words is "six hundred sixty-four billion, five hundred eighty-one million, three hundred forty-seven thousand, eight hundred ninety-seven".