21001123203 has 4 divisors (see below), whose sum is σ = 28001497608. Its totient is φ = 14000748800.

The previous prime is 21001123189. The next prime is 21001123207. The reversal of 21001123203 is 30232110012.

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 21001123203 - 2¹⁰ = 21001122179 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21001123207) 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, 3500187198 + ... + 3500187203.

It is an arithmetic number, because the mean of its divisors is an integer number (7000374402).

Almost surely, 2^21001123203 is an apocalyptic number.

21001123203 is a deficient number, since it is larger than the sum of its proper divisors (7000374405).

21001123203 is an equidigital number, since it uses as much as digits as its factorization.

21001123203 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7000374404.

The product of its (nonzero) digits is 72, while the sum is 15.

Adding to 21001123203 its reverse (30232110012), we get a palindrome (51233233215).

The spelling of 21001123203 in words is "twenty-one billion, one million, one hundred twenty-three thousand, two hundred three".