21085203 has 4 divisors (see below), whose sum is σ = 28113608. Its totient is φ = 14056800.

The previous prime is 21085201. The next prime is 21085213. The reversal of 21085203 is 30258012.

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

It is not a de Polignac number, because 21085203 - 2¹ = 21085201 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21085203.

It is not an unprimeable number, because it can be changed into a prime (21085201) 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, 3514198 + ... + 3514203.

It is an arithmetic number, because the mean of its divisors is an integer number (7028402).

Almost surely, 2^21085203 is an apocalyptic number.

21085203 is a deficient number, since it is larger than the sum of its proper divisors (7028405).

21085203 is an equidigital number, since it uses as much as digits as its factorization.

21085203 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7028404.

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 21085203 is about 4591.8626939402. The cubic root of 21085203 is about 276.2650389361.

The spelling of 21085203 in words is "twenty-one million, eighty-five thousand, two hundred three".