21224403 has 16 divisors (see below), whose sum is σ = 31614240. Its totient is φ = 14072832.

The previous prime is 21224389. The next prime is 21224431. The reversal of 21224403 is 30442212.

It is not a de Polignac number, because 21224403 - 2¹⁰ = 21223379 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21224003) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3175 + ... + 7247.

It is an arithmetic number, because the mean of its divisors is an integer number (1975890).

Almost surely, 2^21224403 is an apocalyptic number.

21224403 is a deficient number, since it is larger than the sum of its proper divisors (10389837).

21224403 is a wasteful number, since it uses less digits than its factorization.

21224403 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4275 (or 4269 counting only the distinct ones).

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

The square root of 21224403 is about 4606.9950075944. The cubic root of 21224403 is about 276.8716535391.

Adding to 21224403 its reverse (30442212), we get a palindrome (51666615).

The spelling of 21224403 in words is "twenty-one million, two hundred twenty-four thousand, four hundred three".