21323331321 has 4 divisors (see below), whose sum is σ = 28431108432. Its totient is φ = 14215554212.

The previous prime is 21323331301. The next prime is 21323331391. The reversal of 21323331321 is 12313332312.

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 not a de Polignac number, because 21323331321 - 2²⁶ = 21256222457 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21323331291 and 21323331300.

It is not an unprimeable number, because it can be changed into a prime (21323331301) 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, 3553888551 + ... + 3553888556.

It is an arithmetic number, because the mean of its divisors is an integer number (7107777108).

Almost surely, 2^21323331321 is an apocalyptic number.

It is an amenable number.

21323331321 is a deficient number, since it is larger than the sum of its proper divisors (7107777111).

21323331321 is an equidigital number, since it uses as much as digits as its factorization.

21323331321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7107777110.

The product of its digits is 1944, while the sum is 24.

Adding to 21323331321 its reverse (12313332312), we get a palindrome (33636663633).

Subtracting from 21323331321 its reverse (12313332312), we obtain a palindrome (9009999009).

The spelling of 21323331321 in words is "twenty-one billion, three hundred twenty-three million, three hundred thirty-one thousand, three hundred twenty-one".