21112291 has 2 divisors, whose sum is σ = 21112292. Its totient is φ = 21112290.

The previous prime is 21112279. The next prime is 21112339. The reversal of 21112291 is 19221112.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21112291 is a prime.

It is not a weakly prime, because it can be changed into another prime (21112241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10556145 + 10556146.

It is an arithmetic number, because the mean of its divisors is an integer number (10556146).

Almost surely, 2^21112291 is an apocalyptic number.

21112291 is a deficient number, since it is larger than the sum of its proper divisors (1).

21112291 is an equidigital number, since it uses as much as digits as its factorization.

21112291 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72, while the sum is 19.

The square root of 21112291 is about 4594.8113127744. The cubic root of 21112291 is about 276.3832935088.

The spelling of 21112291 in words is "twenty-one million, one hundred twelve thousand, two hundred ninety-one".