664250221 has 2 divisors, whose sum is σ = 664250222. Its totient is φ = 664250220.

The previous prime is 664250183. The next prime is 664250239. The reversal of 664250221 is 122052466.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 650964196 + 13286025 = 25514^2 + 3645^2 .

It is a cyclic number.

It is not a de Polignac number, because 664250221 - 2¹¹ = 664248173 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 664250221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (664253221) 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, 332125110 + 332125111.

It is an arithmetic number, because the mean of its divisors is an integer number (332125111).

Almost surely, 2^664250221 is an apocalyptic number.

It is an amenable number.

664250221 is a deficient number, since it is larger than the sum of its proper divisors (1).

664250221 is an equidigital number, since it uses as much as digits as its factorization.

664250221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5760, while the sum is 28.

The square root of 664250221 is about 25773.0522251440. The cubic root of 664250221 is about 872.5237070430.

The spelling of 664250221 in words is "six hundred sixty-four million, two hundred fifty thousand, two hundred twenty-one".