21343243 has 2 divisors, whose sum is σ = 21343244. Its totient is φ = 21343242.

The previous prime is 21343187. The next prime is 21343249. The reversal of 21343243 is 34234312.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21343243 is a prime.

It is not a weakly prime, because it can be changed into another prime (21343249) 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, 10671621 + 10671622.

It is an arithmetic number, because the mean of its divisors is an integer number (10671622).

Almost surely, 2^21343243 is an apocalyptic number.

21343243 is a deficient number, since it is larger than the sum of its proper divisors (1).

21343243 is an equidigital number, since it uses as much as digits as its factorization.

21343243 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1728, while the sum is 22.

The square root of 21343243 is about 4619.8747818529. The cubic root of 21343243 is about 277.3874467121.

Adding to 21343243 its reverse (34234312), we get a palindrome (55577555).

The spelling of 21343243 in words is "twenty-one million, three hundred forty-three thousand, two hundred forty-three".