21033210221 has 2 divisors, whose sum is σ = 21033210222. Its totient is φ = 21033210220.

The previous prime is 21033210157. The next prime is 21033210293. The reversal of 21033210221 is 12201233012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16270278025 + 4762932196 = 127555^2 + 69014^2 .

It is a cyclic number.

It is not a de Polignac number, because 21033210221 - 2⁶ = 21033210157 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21033210221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21033210721) 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, 10516605110 + 10516605111.

It is an arithmetic number, because the mean of its divisors is an integer number (10516605111).

Almost surely, 2^21033210221 is an apocalyptic number.

It is an amenable number.

21033210221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21033210221 is an equidigital number, since it uses as much as digits as its factorization.

21033210221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 144, while the sum is 17.

Adding to 21033210221 its reverse (12201233012), we get a palindrome (33234443233).

The spelling of 21033210221 in words is "twenty-one billion, thirty-three million, two hundred ten thousand, two hundred twenty-one".