21124203 has 4 divisors (see below), whose sum is σ = 28165608. Its totient is φ = 14082800.

The previous prime is 21124199. The next prime is 21124253. The reversal of 21124203 is 30242112.

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 21124203 - 2² = 21124199 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21124253) 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 in 3 ways as a sum of consecutive naturals, for example, 3520698 + ... + 3520703.

It is an arithmetic number, because the mean of its divisors is an integer number (7041402).

Almost surely, 2^21124203 is an apocalyptic number.

21124203 is a deficient number, since it is larger than the sum of its proper divisors (7041405).

21124203 is an equidigital number, since it uses as much as digits as its factorization.

21124203 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7041404.

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 21124203 is about 4596.1073747248. The cubic root of 21124203 is about 276.4352641641.

Adding to 21124203 its reverse (30242112), we get a palindrome (51366315).

The spelling of 21124203 in words is "twenty-one million, one hundred twenty-four thousand, two hundred three".