21221133221 has 2 divisors, whose sum is σ = 21221133222. Its totient is φ = 21221133220.

The previous prime is 21221133209. The next prime is 21221133223. The reversal of 21221133221 is 12233112212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18854310721 + 2366822500 = 137311^2 + 48650^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221133221 - 2¹⁴ = 21221116837 is a prime.

Together with 21221133223, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21221133193 and 21221133202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21221133223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610566610 + 10610566611.

It is an arithmetic number, because the mean of its divisors is an integer number (10610566611).

Almost surely, 2^21221133221 is an apocalyptic number.

It is an amenable number.

21221133221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221133221 is an equidigital number, since it uses as much as digits as its factorization.

21221133221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 288, while the sum is 20.

Adding to 21221133221 its reverse (12233112212), we get a palindrome (33454245433).

The spelling of 21221133221 in words is "twenty-one billion, two hundred twenty-one million, one hundred thirty-three thousand, two hundred twenty-one".