664220801 has 2 divisors, whose sum is σ = 664220802. Its totient is φ = 664220800.

The previous prime is 664220783. The next prime is 664220803. The reversal of 664220801 is 108022466.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 630010000 + 34210801 = 25100^2 + 5849^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-664220801 is a prime.

It is a Sophie Germain prime.

Together with 664220803, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (664220803) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332110400 + 332110401.

It is an arithmetic number, because the mean of its divisors is an integer number (332110401).

Almost surely, 2^664220801 is an apocalyptic number.

It is an amenable number.

664220801 is a deficient number, since it is larger than the sum of its proper divisors (1).

664220801 is an equidigital number, since it uses as much as digits as its factorization.

664220801 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4608, while the sum is 29.

The square root of 664220801 is about 25772.4814676430. The cubic root of 664220801 is about 872.5108253378.

The spelling of 664220801 in words is "six hundred sixty-four million, two hundred twenty thousand, eight hundred one".