21304441 has 2 divisors, whose sum is σ = 21304442. Its totient is φ = 21304440.

The previous prime is 21304427. The next prime is 21304447. The reversal of 21304441 is 14440312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15178816 + 6125625 = 3896^2 + 2475^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21304441 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21304447) 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, 10652220 + 10652221.

It is an arithmetic number, because the mean of its divisors is an integer number (10652221).

Almost surely, 2^21304441 is an apocalyptic number.

It is an amenable number.

21304441 is a deficient number, since it is larger than the sum of its proper divisors (1).

21304441 is an equidigital number, since it uses as much as digits as its factorization.

21304441 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 384, while the sum is 19.

The square root of 21304441 is about 4615.6734069906. The cubic root of 21304441 is about 277.2192480181.

Adding to 21304441 its reverse (14440312), we get a palindrome (35744753).

The spelling of 21304441 in words is "twenty-one million, three hundred four thousand, four hundred forty-one".