21056203 has 4 divisors (see below), whose sum is σ = 24064240. Its totient is φ = 18048168.

The previous prime is 21056179. The next prime is 21056227. The reversal of 21056203 is 30265012.

It is a happy number.

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

It is an interprime number because it is at equal distance from previous prime (21056179) and next prime (21056227).

It is a cyclic number.

It is not a de Polignac number, because 21056203 - 2⁵ = 21056171 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21056263) 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, 1504008 + ... + 1504021.

It is an arithmetic number, because the mean of its divisors is an integer number (6016060).

Almost surely, 2^21056203 is an apocalyptic number.

21056203 is a deficient number, since it is larger than the sum of its proper divisors (3008037).

21056203 is an equidigital number, since it uses as much as digits as its factorization.

21056203 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3008036.

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 21056203 is about 4588.7038474933. The cubic root of 21056203 is about 276.1383250829.

The spelling of 21056203 in words is "twenty-one million, fifty-six thousand, two hundred three".