21252443 has 2 divisors, whose sum is σ = 21252444. Its totient is φ = 21252442.

The previous prime is 21252433. The next prime is 21252457. The reversal of 21252443 is 34425212.

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-21252443 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21252403) 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, 10626221 + 10626222.

It is an arithmetic number, because the mean of its divisors is an integer number (10626222).

Almost surely, 2^21252443 is an apocalyptic number.

21252443 is a deficient number, since it is larger than the sum of its proper divisors (1).

21252443 is an equidigital number, since it uses as much as digits as its factorization.

21252443 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1920, while the sum is 23.

The square root of 21252443 is about 4610.0372015853. The cubic root of 21252443 is about 276.9935268507.

Adding to 21252443 its reverse (34425212), we get a palindrome (55677655).

The spelling of 21252443 in words is "twenty-one million, two hundred fifty-two thousand, four hundred forty-three".