21030313 has 2 divisors, whose sum is σ = 21030314. Its totient is φ = 21030312.

The previous prime is 21030301. The next prime is 21030329. The reversal of 21030313 is 31303012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16548624 + 4481689 = 4068^2 + 2117^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21030313 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21030293 and 21030302.

It is not a weakly prime, because it can be changed into another prime (21030613) 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, 10515156 + 10515157.

It is an arithmetic number, because the mean of its divisors is an integer number (10515157).

Almost surely, 2^21030313 is an apocalyptic number.

It is an amenable number.

21030313 is a deficient number, since it is larger than the sum of its proper divisors (1).

21030313 is an equidigital number, since it uses as much as digits as its factorization.

21030313 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 54, while the sum is 13.

The square root of 21030313 is about 4585.8819217245. The cubic root of 21030313 is about 276.0251018617.

Adding to 21030313 its reverse (31303012), we get a palindrome (52333325).

The spelling of 21030313 in words is "twenty-one million, thirty thousand, three hundred thirteen".