21333133 has 2 divisors, whose sum is σ = 21333134. Its totient is φ = 21333132.

The previous prime is 21333107. The next prime is 21333139. The reversal of 21333133 is 33133312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19518724 + 1814409 = 4418^2 + 1347^2 .

It is a cyclic number.

It is not a de Polignac number, because 21333133 - 2⁹ = 21332621 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21333133.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21333139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10666566 + 10666567.

It is an arithmetic number, because the mean of its divisors is an integer number (10666567).

Almost surely, 2^21333133 is an apocalyptic number.

It is an amenable number.

21333133 is a deficient number, since it is larger than the sum of its proper divisors (1).

21333133 is an equidigital number, since it uses as much as digits as its factorization.

21333133 is an evil number, because the sum of its binary digits is even.

The product of its digits is 486, while the sum is 19.

The square root of 21333133 is about 4618.7804667466. The cubic root of 21333133 is about 277.3436415914.

Adding to 21333133 its reverse (33133312), we get a palindrome (54466445).

The spelling of 21333133 in words is "twenty-one million, three hundred thirty-three thousand, one hundred thirty-three".