21203 has 8 divisors (see below), whose sum is σ = 26208. Its totient is φ = 16704.

The previous prime is 21193. The next prime is 21211. The reversal of 21203 is 30212.

21203 = 52² + 53² + ... + 58².

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

It is a cyclic number.

It is not a de Polignac number, because 21203 - 2⁴ = 21187 is a prime.

It is a nialpdrome in base 13.

It is not an unprimeable number, because it can be changed into a prime (21283) 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, 26 + ... + 207.

It is an arithmetic number, because the mean of its divisors is an integer number (3276).

2²¹²⁰³ is an apocalyptic number.

21203 is a deficient number, since it is larger than the sum of its proper divisors (5005).

21203 is a wasteful number, since it uses less digits than its factorization.

21203 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 253.

The product of its (nonzero) digits is 12, while the sum is 8.

The square root of 21203 is about 145.6124994635. The cubic root of 21203 is about 27.6778555090.

Adding to 21203 its reverse (30212), we get a palindrome (51415).

Subtracting 21203 from its reverse (30212), we obtain a palindrome (9009).

The spelling of 21203 in words is "twenty-one thousand, two hundred three", and thus it is an iban number.