21055203 has 36 divisors (see below), whose sum is σ = 33496320. Its totient is φ = 12737088.

The previous prime is 21055147. The next prime is 21055207. The reversal of 21055203 is 30255012.

It is a happy number.

It is not a de Polignac number, because 21055203 - 2¹⁰ = 21054179 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21055207) 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 35 ways as a sum of consecutive naturals, for example, 165726 + ... + 165852.

Almost surely, 2^21055203 is an apocalyptic number.

21055203 is a deficient number, since it is larger than the sum of its proper divisors (12441117).

21055203 is a wasteful number, since it uses less digits than its factorization.

21055203 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 268 (or 252 counting only the distinct ones).

The product of its (nonzero) digits is 300, while the sum is 18.

The square root of 21055203 is about 4588.5948829680. The cubic root of 21055203 is about 276.1339535651.

The spelling of 21055203 in words is "twenty-one million, fifty-five thousand, two hundred three".