21210313 has 2 divisors, whose sum is σ = 21210314. Its totient is φ = 21210312.

The previous prime is 21210307. The next prime is 21210317. The reversal of 21210313 is 31301212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21040569 + 169744 = 4587^2 + 412^2 .

It is a cyclic number.

It is not a de Polignac number, because 21210313 - 2⁹ = 21209801 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21210293 and 21210302.

It is not a weakly prime, because it can be changed into another prime (21210317) 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, 10605156 + 10605157.

It is an arithmetic number, because the mean of its divisors is an integer number (10605157).

Almost surely, 2^21210313 is an apocalyptic number.

It is an amenable number.

21210313 is a deficient number, since it is larger than the sum of its proper divisors (1).

21210313 is an equidigital number, since it uses as much as digits as its factorization.

21210313 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36, while the sum is 13.

The square root of 21210313 is about 4605.4655573568. The cubic root of 21210313 is about 276.8103721110.

Adding to 21210313 its reverse (31301212), we get a palindrome (52511525).

The spelling of 21210313 in words is "twenty-one million, two hundred ten thousand, three hundred thirteen".