21243713 has 2 divisors, whose sum is σ = 21243714. Its totient is φ = 21243712.

The previous prime is 21243709. The next prime is 21243721. The reversal of 21243713 is 31734212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20584369 + 659344 = 4537^2 + 812^2 .

It is a cyclic number.

It is not a de Polignac number, because 21243713 - 2² = 21243709 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21243793) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10621856 + 10621857.

It is an arithmetic number, because the mean of its divisors is an integer number (10621857).

Almost surely, 2^21243713 is an apocalyptic number.

It is an amenable number.

21243713 is a deficient number, since it is larger than the sum of its proper divisors (1).

21243713 is an equidigital number, since it uses as much as digits as its factorization.

21243713 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1008, while the sum is 23.

The square root of 21243713 is about 4609.0902573067. The cubic root of 21243713 is about 276.9555941971.

Adding to 21243713 its reverse (31734212), we get a palindrome (52977925).

The spelling of 21243713 in words is "twenty-one million, two hundred forty-three thousand, seven hundred thirteen".