21321133 has 2 divisors, whose sum is σ = 21321134. Its totient is φ = 21321132.

The previous prime is 21321121. The next prime is 21321169. The reversal of 21321133 is 33112312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17623204 + 3697929 = 4198^2 + 1923^2 .

It is a cyclic number.

It is not a de Polignac number, because 21321133 - 2⁵ = 21321101 is a prime.

It is a plaindrome in base 16.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21321193) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10660566 + 10660567.

It is an arithmetic number, because the mean of its divisors is an integer number (10660567).

Almost surely, 2^21321133 is an apocalyptic number.

It is an amenable number.

21321133 is a deficient number, since it is larger than the sum of its proper divisors (1).

21321133 is an equidigital number, since it uses as much as digits as its factorization.

21321133 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 108, while the sum is 16.

The square root of 21321133 is about 4617.4812398103. The cubic root of 21321133 is about 277.2916294167.

Adding to 21321133 its reverse (33112312), we get a palindrome (54433445).

The spelling of 21321133 in words is "twenty-one million, three hundred twenty-one thousand, one hundred thirty-three".