21424313 has 2 divisors, whose sum is σ = 21424314. Its totient is φ = 21424312.

The previous prime is 21424303. The next prime is 21424327. The reversal of 21424313 is 31342412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21418384 + 5929 = 4628^2 + 77^2 .

It is a cyclic number.

It is not a de Polignac number, because 21424313 - 2⁴ = 21424297 is a prime.

It is not a weakly prime, because it can be changed into another prime (21424303) 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, 10712156 + 10712157.

It is an arithmetic number, because the mean of its divisors is an integer number (10712157).

Almost surely, 2^21424313 is an apocalyptic number.

It is an amenable number.

21424313 is a deficient number, since it is larger than the sum of its proper divisors (1).

21424313 is an equidigital number, since it uses as much as digits as its factorization.

21424313 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 576, while the sum is 20.

The square root of 21424313 is about 4628.6405131529. The cubic root of 21424313 is about 277.7382117097.

Adding to 21424313 its reverse (31342412), we get a palindrome (52766725).

The spelling of 21424313 in words is "twenty-one million, four hundred twenty-four thousand, three hundred thirteen".