21304443 has 4 divisors (see below), whose sum is σ = 28405928. Its totient is φ = 14202960.

The previous prime is 21304441. The next prime is 21304447. The reversal of 21304443 is 34440312.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21304443 - 2¹ = 21304441 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21304441) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3550738 + ... + 3550743.

It is an arithmetic number, because the mean of its divisors is an integer number (7101482).

Almost surely, 2^21304443 is an apocalyptic number.

21304443 is a deficient number, since it is larger than the sum of its proper divisors (7101485).

21304443 is an equidigital number, since it uses as much as digits as its factorization.

21304443 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7101484.

The product of its (nonzero) digits is 1152, while the sum is 21.

The square root of 21304443 is about 4615.6736236437. The cubic root of 21304443 is about 277.2192566930.

Adding to 21304443 its reverse (34440312), we get a palindrome (55744755).

The spelling of 21304443 in words is "twenty-one million, three hundred four thousand, four hundred forty-three".