21333221321 has 2 divisors, whose sum is σ = 21333221322. Its totient is φ = 21333221320.

The previous prime is 21333221293. The next prime is 21333221333. The reversal of 21333221321 is 12312233312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18330181321 + 3003040000 = 135389^2 + 54800^2 .

It is a cyclic number.

It is not a de Polignac number, because 21333221321 - 2¹⁸ = 21332959177 is a prime.

It is not a weakly prime, because it can be changed into another prime (21333221381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10666610660 + 10666610661.

It is an arithmetic number, because the mean of its divisors is an integer number (10666610661).

Almost surely, 2^21333221321 is an apocalyptic number.

It is an amenable number.

21333221321 is a deficient number, since it is larger than the sum of its proper divisors (1).

21333221321 is an equidigital number, since it uses as much as digits as its factorization.

21333221321 is an evil number, because the sum of its binary digits is even.

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

Adding to 21333221321 its reverse (12312233312), we get a palindrome (33645454633).

The spelling of 21333221321 in words is "twenty-one billion, three hundred thirty-three million, two hundred twenty-one thousand, three hundred twenty-one".