21323323121 has 4 divisors (see below), whose sum is σ = 21340562292. Its totient is φ = 21306083952.

The previous prime is 21323323093. The next prime is 21323323127. The reversal of 21323323121 is 12132332312.

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 5657296225 + 15666026896 = 75215^2 + 125164^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21323323121 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21323323127) 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, 8617730 + ... + 8620203.

It is an arithmetic number, because the mean of its divisors is an integer number (5335140573).

Almost surely, 2^21323323121 is an apocalyptic number.

It is an amenable number.

21323323121 is a deficient number, since it is larger than the sum of its proper divisors (17239171).

21323323121 is a wasteful number, since it uses less digits than its factorization.

21323323121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17239170.

The product of its digits is 1296, while the sum is 23.

Adding to 21323323121 its reverse (12132332312), we get a palindrome (33455655433).

The spelling of 21323323121 in words is "twenty-one billion, three hundred twenty-three million, three hundred twenty-three thousand, one hundred twenty-one".