21222211 has 2 divisors, whose sum is σ = 21222212. Its totient is φ = 21222210.

The previous prime is 21222181. The next prime is 21222251. The reversal of 21222211 is 11222212.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21222211 - 2¹⁷ = 21091139 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21222191 and 21222200.

It is not a weakly prime, because it can be changed into another prime (21222251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10611105 + 10611106.

It is an arithmetic number, because the mean of its divisors is an integer number (10611106).

Almost surely, 2^21222211 is an apocalyptic number.

21222211 is a deficient number, since it is larger than the sum of its proper divisors (1).

21222211 is an equidigital number, since it uses as much as digits as its factorization.

21222211 is an evil number, because the sum of its binary digits is even.

The product of its digits is 32, while the sum is 13.

The square root of 21222211 is about 4606.7571023443. The cubic root of 21222211 is about 276.8621216878.

Adding to 21222211 its reverse (11222212), we get a palindrome (32444423).

Subtracting from 21222211 its reverse (11222212), we obtain a palindrome (9999999).

The spelling of 21222211 in words is "twenty-one million, two hundred twenty-two thousand, two hundred eleven".