21220211 has 2 divisors, whose sum is σ = 21220212. Its totient is φ = 21220210.

The previous prime is 21220159. The next prime is 21220219. The reversal of 21220211 is 11202212.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21220211 - 2¹⁴ = 21203827 is a prime.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 21220192 and 21220201.

It is not a weakly prime, because it can be changed into another prime (21220219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610105 + 10610106.

It is an arithmetic number, because the mean of its divisors is an integer number (10610106).

Almost surely, 2^21220211 is an apocalyptic number.

21220211 is a deficient number, since it is larger than the sum of its proper divisors (1).

21220211 is an equidigital number, since it uses as much as digits as its factorization.

21220211 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 21220211 is about 4606.5400247908. The cubic root of 21220211 is about 276.8534241706.

Adding to 21220211 its reverse (11202212), we get a palindrome (32422423).

The spelling of 21220211 in words is "twenty-one million, two hundred twenty thousand, two hundred eleven".