21221033 has 2 divisors, whose sum is σ = 21221034. Its totient is φ = 21221032.

The previous prime is 21221021. The next prime is 21221047. The reversal of 21221033 is 33012212.

It is a happy number.

It is an a-pointer prime, because the next prime (21221047) can be obtained adding 21221033 to its sum of digits (14).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17952169 + 3268864 = 4237^2 + 1808^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221033 - 2²⁰ = 20172457 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21220999 and 21221017.

It is not a weakly prime, because it can be changed into another prime (21221003) 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, 10610516 + 10610517.

It is an arithmetic number, because the mean of its divisors is an integer number (10610517).

Almost surely, 2^21221033 is an apocalyptic number.

It is an amenable number.

21221033 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221033 is an equidigital number, since it uses as much as digits as its factorization.

21221033 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 21221033 is about 4606.6292449035. The cubic root of 21221033 is about 276.8569989163.

Adding to 21221033 its reverse (33012212), we get a palindrome (54233245).

The spelling of 21221033 in words is "twenty-one million, two hundred twenty-one thousand, thirty-three".