663222221 has 2 divisors, whose sum is σ = 663222222. Its totient is φ = 663222220.

The previous prime is 663222211. The next prime is 663222229. The reversal of 663222221 is 122222366.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 635544100 + 27678121 = 25210^2 + 5261^2 .

It is a cyclic number.

It is not a de Polignac number, because 663222221 - 2¹⁰ = 663221197 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a nialpdrome in base 10.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (663222229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 331611110 + 331611111.

It is an arithmetic number, because the mean of its divisors is an integer number (331611111).

Almost surely, 2^663222221 is an apocalyptic number.

It is an amenable number.

663222221 is a deficient number, since it is larger than the sum of its proper divisors (1).

663222221 is an equidigital number, since it uses as much as digits as its factorization.

663222221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3456, while the sum is 26.

The square root of 663222221 is about 25753.1011918953. The cubic root of 663222221 is about 872.0733659654.

Adding to 663222221 its reverse (122222366), we get a palindrome (785444587).

The spelling of 663222221 in words is "six hundred sixty-three million, two hundred twenty-two thousand, two hundred twenty-one".