21222200221 has 2 divisors, whose sum is σ = 21222200222. Its totient is φ = 21222200220.

The previous prime is 21222200201. The next prime is 21222200239. The reversal of 21222200221 is 12200222212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21061265625 + 160934596 = 145125^2 + 12686^2 .

It is a cyclic number.

It is not a de Polignac number, because 21222200221 - 2³³ = 12632265629 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21222200195 and 21222200204.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21222200201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10611100110 + 10611100111.

It is an arithmetic number, because the mean of its divisors is an integer number (10611100111).

Almost surely, 2^21222200221 is an apocalyptic number.

It is an amenable number.

21222200221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21222200221 is an equidigital number, since it uses as much as digits as its factorization.

21222200221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 128, while the sum is 16.

Adding to 21222200221 its reverse (12200222212), we get a palindrome (33422422433).

The spelling of 21222200221 in words is "twenty-one billion, two hundred twenty-two million, two hundred thousand, two hundred twenty-one".