21421215203 has 4 divisors (see below), whose sum is σ = 21517274688. Its totient is φ = 21325155720.

The previous prime is 21421215199. The next prime is 21421215223. The reversal of 21421215203 is 30251212412.

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 21421215203 - 2² = 21421215199 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21421215223) 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, 48029408 + ... + 48029853.

It is an arithmetic number, because the mean of its divisors is an integer number (5379318672).

Almost surely, 2^21421215203 is an apocalyptic number.

21421215203 is a deficient number, since it is larger than the sum of its proper divisors (96059485).

21421215203 is an equidigital number, since it uses as much as digits as its factorization.

21421215203 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96059484.

The product of its (nonzero) digits is 960, while the sum is 23.

Adding to 21421215203 its reverse (30251212412), we get a palindrome (51672427615).

The spelling of 21421215203 in words is "twenty-one billion, four hundred twenty-one million, two hundred fifteen thousand, two hundred three".