21044203 has 4 divisors (see below), whose sum is σ = 21492000. Its totient is φ = 20596408.

The previous prime is 21044197. The next prime is 21044213. The reversal of 21044203 is 30244012.

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

It is a cyclic number.

It is not a de Polignac number, because 21044203 - 2⁹ = 21043691 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21044213) 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 3 ways as a sum of consecutive naturals, for example, 223828 + ... + 223921.

It is an arithmetic number, because the mean of its divisors is an integer number (5373000).

Almost surely, 2^21044203 is an apocalyptic number.

21044203 is a deficient number, since it is larger than the sum of its proper divisors (447797).

21044203 is an equidigital number, since it uses as much as digits as its factorization.

21044203 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 447796.

The product of its (nonzero) digits is 192, while the sum is 16.

The square root of 21044203 is about 4587.3961023657. The cubic root of 21044203 is about 276.0858577318.

Adding to 21044203 its reverse (30244012), we get a palindrome (51288215).

The spelling of 21044203 in words is "twenty-one million, forty-four thousand, two hundred three".