21222611 has 2 divisors, whose sum is σ = 21222612. Its totient is φ = 21222610.

The previous prime is 21222587. The next prime is 21222653. The reversal of 21222611 is 11622212.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21222611 is a prime.

It is a Sophie Germain prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21222611.

It is not a weakly prime, because it can be changed into another prime (21222671) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10611305 + 10611306.

It is an arithmetic number, because the mean of its divisors is an integer number (10611306).

Almost surely, 2^21222611 is an apocalyptic number.

21222611 is a deficient number, since it is larger than the sum of its proper divisors (1).

21222611 is an equidigital number, since it uses as much as digits as its factorization.

21222611 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 96, while the sum is 17.

The square root of 21222611 is about 4606.8005166276. The cubic root of 21222611 is about 276.8638611257.

Adding to 21222611 its reverse (11622212), we get a palindrome (32844823).

The spelling of 21222611 in words is "twenty-one million, two hundred twenty-two thousand, six hundred eleven".