21916211 has 2 divisors, whose sum is σ = 21916212. Its totient is φ = 21916210.

The previous prime is 21916207. The next prime is 21916229. The reversal of 21916211 is 11261912.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21916211 - 2² = 21916207 is a prime.

It is not a weakly prime, because it can be changed into another prime (21916201) 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, 10958105 + 10958106.

It is an arithmetic number, because the mean of its divisors is an integer number (10958106).

Almost surely, 2^21916211 is an apocalyptic number.

21916211 is a deficient number, since it is larger than the sum of its proper divisors (1).

21916211 is an equidigital number, since it uses as much as digits as its factorization.

21916211 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 216, while the sum is 23.

The square root of 21916211 is about 4681.4753016544. The cubic root of 21916211 is about 279.8477531168.

The spelling of 21916211 in words is "twenty-one million, nine hundred sixteen thousand, two hundred eleven".