21333305 has 16 divisors (see below), whose sum is σ = 30530304. Its totient is φ = 13992000.

The previous prime is 21333271. The next prime is 21333329. The reversal of 21333305 is 50333312.

It is not a de Polignac number, because 21333305 - 2⁸ = 21333049 is a prime.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 12446 + ... + 14055.

It is an arithmetic number, because the mean of its divisors is an integer number (1908144).

Almost surely, 2^21333305 is an apocalyptic number.

It is an amenable number.

21333305 is a deficient number, since it is larger than the sum of its proper divisors (9196999).

21333305 is a wasteful number, since it uses less digits than its factorization.

21333305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26536.

The product of its (nonzero) digits is 810, while the sum is 20.

The square root of 21333305 is about 4618.7990863427. The cubic root of 21333305 is about 277.3443869575.

Adding to 21333305 its reverse (50333312), we get a palindrome (71666617).

The spelling of 21333305 in words is "twenty-one million, three hundred thirty-three thousand, three hundred five".