21230213 has 2 divisors, whose sum is σ = 21230214. Its totient is φ = 21230212.

The previous prime is 21230203. The next prime is 21230227. The reversal of 21230213 is 31203212.

It is a happy number.

It is an a-pointer prime, because the next prime (21230227) can be obtained adding 21230213 to its sum of digits (14).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14915044 + 6315169 = 3862^2 + 2513^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21230213 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21230203) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10615106 + 10615107.

It is an arithmetic number, because the mean of its divisors is an integer number (10615107).

Almost surely, 2^21230213 is an apocalyptic number.

It is an amenable number.

21230213 is a deficient number, since it is larger than the sum of its proper divisors (1).

21230213 is an equidigital number, since it uses as much as digits as its factorization.

21230213 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 21230213 is about 4607.6255273188. The cubic root of 21230213 is about 276.8969149885.

Adding to 21230213 its reverse (31203212), we get a palindrome (52433425).

The spelling of 21230213 in words is "twenty-one million, two hundred thirty thousand, two hundred thirteen".