21330210221 has 2 divisors, whose sum is σ = 21330210222. Its totient is φ = 21330210220.

The previous prime is 21330210211. The next prime is 21330210247. The reversal of 21330210221 is 12201203312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18006687721 + 3323522500 = 134189^2 + 57650^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21330210221 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21330210221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21330210211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10665105110 + 10665105111.

It is an arithmetic number, because the mean of its divisors is an integer number (10665105111).

Almost surely, 2^21330210221 is an apocalyptic number.

It is an amenable number.

21330210221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21330210221 is an equidigital number, since it uses as much as digits as its factorization.

21330210221 is an evil number, because the sum of its binary digits is even.

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

Adding to 21330210221 its reverse (12201203312), we get a palindrome (33531413533).

The spelling of 21330210221 in words is "twenty-one billion, three hundred thirty million, two hundred ten thousand, two hundred twenty-one".