664200521 has 2 divisors, whose sum is σ = 664200522. Its totient is φ = 664200520.

The previous prime is 664200473. The next prime is 664200541. The reversal of 664200521 is 125002466.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 657204496 + 6996025 = 25636^2 + 2645^2 .

It is a cyclic number.

It is not a de Polignac number, because 664200521 - 2¹⁴ = 664184137 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (664200541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332100260 + 332100261.

It is an arithmetic number, because the mean of its divisors is an integer number (332100261).

Almost surely, 2^664200521 is an apocalyptic number.

It is an amenable number.

664200521 is a deficient number, since it is larger than the sum of its proper divisors (1).

664200521 is an equidigital number, since it uses as much as digits as its factorization.

664200521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2880, while the sum is 26.

The square root of 664200521 is about 25772.0880217339. The cubic root of 664200521 is about 872.5019454094.

Adding to 664200521 its reverse (125002466), we get a palindrome (789202987).

The spelling of 664200521 in words is "six hundred sixty-four million, two hundred thousand, five hundred twenty-one".