21333533 has 8 divisors (see below), whose sum is σ = 23017176. Its totient is φ = 19656000.

The previous prime is 21333511. The next prime is 21333539. The reversal of 21333533 is 33533312.

It can be written as a sum of positive squares in 4 ways, for example, as 4507129 + 16826404 = 2123^2 + 4102^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21333533 - 2¹² = 21329437 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21333499 and 21333508.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21333539) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7943 + ... + 10283.

It is an arithmetic number, because the mean of its divisors is an integer number (2877147).

Almost surely, 2^21333533 is an apocalyptic number.

It is an amenable number.

21333533 is a deficient number, since it is larger than the sum of its proper divisors (1683643).

21333533 is a wasteful number, since it uses less digits than its factorization.

21333533 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3055.

The product of its digits is 2430, while the sum is 23.

The square root of 21333533 is about 4618.8237680171. The cubic root of 21333533 is about 277.3453749946.

Adding to 21333533 its reverse (33533312), we get a palindrome (54866845).

The spelling of 21333533 in words is "twenty-one million, three hundred thirty-three thousand, five hundred thirty-three".