21124232321 has 4 divisors (see below), whose sum is σ = 21126930132. Its totient is φ = 21121534512.

The previous prime is 21124232299. The next prime is 21124232341. The reversal of 21124232321 is 12323242112.

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

It can be written as a sum of positive squares in 2 ways, for example, as 2165971600 + 18958260721 = 46540^2 + 137689^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21124232321 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21124232341) 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, 1337126 + ... + 1352831.

It is an arithmetic number, because the mean of its divisors is an integer number (5281732533).

Almost surely, 2^21124232321 is an apocalyptic number.

It is an amenable number.

21124232321 is a deficient number, since it is larger than the sum of its proper divisors (2697811).

21124232321 is an equidigital number, since it uses as much as digits as its factorization.

21124232321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2697810.

The product of its digits is 1152, while the sum is 23.

Adding to 21124232321 its reverse (12323242112), we get a palindrome (33447474433).

The spelling of 21124232321 in words is "twenty-one billion, one hundred twenty-four million, two hundred thirty-two thousand, three hundred twenty-one".