664108321 has 2 divisors, whose sum is σ = 664108322. Its totient is φ = 664108320.

The previous prime is 664108271. The next prime is 664108327. The reversal of 664108321 is 123801466.

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., 546624400 + 117483921 = 23380^2 + 10839^2 .

It is a cyclic number.

It is not a de Polignac number, because 664108321 - 2⁹ = 664107809 is a prime.

It is not a weakly prime, because it can be changed into another prime (664108327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332054160 + 332054161.

It is an arithmetic number, because the mean of its divisors is an integer number (332054161).

Almost surely, 2^664108321 is an apocalyptic number.

It is an amenable number.

664108321 is a deficient number, since it is larger than the sum of its proper divisors (1).

664108321 is an equidigital number, since it uses as much as digits as its factorization.

664108321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6912, while the sum is 31.

The square root of 664108321 is about 25770.2992027644. The cubic root of 664108321 is about 872.4615718578.

Adding to 664108321 its reverse (123801466), we get a palindrome (787909787).

The spelling of 664108321 in words is "six hundred sixty-four million, one hundred eight thousand, three hundred twenty-one".