21230243 has 2 divisors, whose sum is σ = 21230244. Its totient is φ = 21230242.

The previous prime is 21230227. The next prime is 21230249. The reversal of 21230243 is 34203212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21230243 - 2⁴ = 21230227 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21230249) 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, 10615121 + 10615122.

It is an arithmetic number, because the mean of its divisors is an integer number (10615122).

Almost surely, 2^21230243 is an apocalyptic number.

21230243 is a deficient number, since it is larger than the sum of its proper divisors (1).

21230243 is an equidigital number, since it uses as much as digits as its factorization.

21230243 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 288, while the sum is 17.

The square root of 21230243 is about 4607.6287827906. The cubic root of 21230243 is about 276.8970454143.

Adding to 21230243 its reverse (34203212), we get a palindrome (55433455).

The spelling of 21230243 in words is "twenty-one million, two hundred thirty thousand, two hundred forty-three".