21221333321 has 4 divisors (see below), whose sum is σ = 21267367044. Its totient is φ = 21175299600.

The previous prime is 21221333317. The next prime is 21221333333. The reversal of 21221333321 is 12333312212.

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 10761157696 + 10460175625 = 103736^2 + 102275^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221333321 - 2² = 21221333317 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21221333621) 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, 23016170 + ... + 23017091.

It is an arithmetic number, because the mean of its divisors is an integer number (5316841761).

Almost surely, 2^21221333321 is an apocalyptic number.

It is an amenable number.

21221333321 is a deficient number, since it is larger than the sum of its proper divisors (46033723).

21221333321 is an equidigital number, since it uses as much as digits as its factorization.

21221333321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46033722.

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

Adding to 21221333321 its reverse (12333312212), we get a palindrome (33554645533).

The spelling of 21221333321 in words is "twenty-one billion, two hundred twenty-one million, three hundred thirty-three thousand, three hundred twenty-one".