21203203 has 8 divisors (see below), whose sum is σ = 24382208. Its totient is φ = 18061704.

The previous prime is 21203197. The next prime is 21203213. The reversal of 21203203 is 30230212.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21203203 - 2¹⁷ = 21072131 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21203213) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8151 + ... + 10432.

It is an arithmetic number, because the mean of its divisors is an integer number (3047776).

Almost surely, 2^21203203 is an apocalyptic number.

21203203 is a deficient number, since it is larger than the sum of its proper divisors (3179005).

21203203 is a wasteful number, since it uses less digits than its factorization.

21203203 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18753.

The product of its (nonzero) digits is 72, while the sum is 13.

The square root of 21203203 is about 4604.6935837252. The cubic root of 21203203 is about 276.7794383902.

Adding to 21203203 its reverse (30230212), we get a palindrome (51433415).

The spelling of 21203203 in words is "twenty-one million, two hundred three thousand, two hundred three".