21210440203 has 4 divisors (see below), whose sum is σ = 21262299880. Its totient is φ = 21158580528.

The previous prime is 21210440177. The next prime is 21210440257. The reversal of 21210440203 is 30204401212.

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

It is a cyclic number.

It is not a de Polignac number, because 21210440203 - 2⁵ = 21210440171 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21210440263) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25929225 + ... + 25930042.

It is an arithmetic number, because the mean of its divisors is an integer number (5315574970).

Almost surely, 2^21210440203 is an apocalyptic number.

21210440203 is a deficient number, since it is larger than the sum of its proper divisors (51859677).

21210440203 is an equidigital number, since it uses as much as digits as its factorization.

21210440203 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51859676.

The product of its (nonzero) digits is 384, while the sum is 19.

Adding to 21210440203 its reverse (30204401212), we get a palindrome (51414841415).

The spelling of 21210440203 in words is "twenty-one billion, two hundred ten million, four hundred forty thousand, two hundred three".