21113243 has 2 divisors, whose sum is σ = 21113244. Its totient is φ = 21113242.

The previous prime is 21113231. The next prime is 21113251. The reversal of 21113243 is 34231112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21113243 - 2²⁴ = 4336027 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21113843) 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, 10556621 + 10556622.

It is an arithmetic number, because the mean of its divisors is an integer number (10556622).

Almost surely, 2^21113243 is an apocalyptic number.

21113243 is a deficient number, since it is larger than the sum of its proper divisors (1).

21113243 is an equidigital number, since it uses as much as digits as its factorization.

21113243 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 144, while the sum is 17.

The square root of 21113243 is about 4594.9149067203. The cubic root of 21113243 is about 276.3874476914.

Adding to 21113243 its reverse (34231112), we get a palindrome (55344355).

The spelling of 21113243 in words is "twenty-one million, one hundred thirteen thousand, two hundred forty-three".