21234431203 has 4 divisors (see below), whose sum is σ = 21551363080. Its totient is φ = 20917499328.

The previous prime is 21234431191. The next prime is 21234431209. The reversal of 21234431203 is 30213443212.

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 21234431203 - 2²¹ = 21232334051 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21234431209) 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, 158465838 + ... + 158465971.

It is an arithmetic number, because the mean of its divisors is an integer number (5387840770).

Almost surely, 2^21234431203 is an apocalyptic number.

21234431203 is a deficient number, since it is larger than the sum of its proper divisors (316931877).

21234431203 is an equidigital number, since it uses as much as digits as its factorization.

21234431203 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 316931876.

The product of its (nonzero) digits is 3456, while the sum is 25.

Adding to 21234431203 its reverse (30213443212), we get a palindrome (51447874415).

The spelling of 21234431203 in words is "twenty-one billion, two hundred thirty-four million, four hundred thirty-one thousand, two hundred three".