21220443 has 12 divisors (see below), whose sum is σ = 31072600. Its totient is φ = 13952736.

The previous prime is 21220429. The next prime is 21220477. The reversal of 21220443 is 34402212.

21220443 is a `hidden beast` number, since 2 + 1 + 220 + 443 = 666.

It is not a de Polignac number, because 21220443 - 2⁶ = 21220379 is a prime.

It is a super-2 number, since 2×21220443² = 900614402232498, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21221443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 15493 + ... + 16806.

Almost surely, 2^21220443 is an apocalyptic number.

21220443 is a deficient number, since it is larger than the sum of its proper divisors (9852157).

21220443 is a wasteful number, since it uses less digits than its factorization.

21220443 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32378 (or 32375 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

The square root of 21220443 is about 4606.5652063115. The cubic root of 21220443 is about 276.8544331106.

Adding to 21220443 its reverse (34402212), we get a palindrome (55622655).

The spelling of 21220443 in words is "twenty-one million, two hundred twenty thousand, four hundred forty-three".