21233144321 has 4 divisors (see below), whose sum is σ = 21266794944. Its totient is φ = 21199493700.

The previous prime is 21233144227. The next prime is 21233144327. The reversal of 21233144321 is 12344133212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21233144321 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21233144327) 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, 16824365 + ... + 16825626.

It is an arithmetic number, because the mean of its divisors is an integer number (5316698736).

Almost surely, 2^21233144321 is an apocalyptic number.

It is an amenable number.

21233144321 is a deficient number, since it is larger than the sum of its proper divisors (33650623).

21233144321 is an equidigital number, since it uses as much as digits as its factorization.

21233144321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33650622.

The product of its digits is 3456, while the sum is 26.

Adding to 21233144321 its reverse (12344133212), we get a palindrome (33577277533).

It can be divided in two parts, 212331 and 44321, that added together give a palindrome (256652).

The spelling of 21233144321 in words is "twenty-one billion, two hundred thirty-three million, one hundred forty-four thousand, three hundred twenty-one".