21304413 has 12 divisors (see below), whose sum is σ = 33140380. Its totient is φ = 13110336.

The previous prime is 21304397. The next prime is 21304427. The reversal of 21304413 is 31440312.

It can be written as a sum of positive squares in 2 ways, for example, as 8538084 + 12766329 = 2922^2 + 3573^2 .

It is not a de Polignac number, because 21304413 - 2⁴ = 21304397 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21305413) 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 in 11 ways as a sum of consecutive naturals, for example, 90928 + ... + 91161.

Almost surely, 2^21304413 is an apocalyptic number.

It is an amenable number.

21304413 is a deficient number, since it is larger than the sum of its proper divisors (11835967).

21304413 is a wasteful number, since it uses less digits than its factorization.

21304413 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 182108 (or 182105 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 21304413 is about 4615.6703738460. The cubic root of 21304413 is about 277.2191265702.

Adding to 21304413 its reverse (31440312), we get a palindrome (52744725).

The spelling of 21304413 in words is "twenty-one million, three hundred four thousand, four hundred thirteen".