21222202122221 has 2 divisors, whose sum is σ = 21222202122222. Its totient is φ = 21222202122220.

The previous prime is 21222202122193. The next prime is 21222202122229. The reversal of 21222202122221 is 12222120222212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11081002646596 + 10141199475625 = 3328814^2 + 3184525^2 .

It is a cyclic number.

It is not a de Polignac number, because 21222202122221 - 2³⁸ = 20947324215277 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21222202122229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10611101061110 + 10611101061111.

It is an arithmetic number, because the mean of its divisors is an integer number (10611101061111).

Almost surely, 2^{21222202122221} is an apocalyptic number.

It is an amenable number.

21222202122221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21222202122221 is an equidigital number, since it uses as much as digits as its factorization.

21222202122221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1024, while the sum is 23.

Adding to 21222202122221 its reverse (12222120222212), we get a palindrome (33444322344433).

The spelling of 21222202122221 in words is "twenty-one trillion, two hundred twenty-two billion, two hundred two million, one hundred twenty-two thousand, two hundred twenty-one".