21333313 has 4 divisors (see below), whose sum is σ = 21416580. Its totient is φ = 21250048.

The previous prime is 21333271. The next prime is 21333329. The reversal of 21333313 is 31333312.

21333313 is nontrivially palindromic in base 16.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 18122049 + 3211264 = 4257^2 + 1792^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21333313 is a prime.

It is a super-2 number, since 2×21333313² = 910220487111938, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21333353) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 41248 + ... + 41761.

It is an arithmetic number, because the mean of its divisors is an integer number (5354145).

Almost surely, 2^21333313 is an apocalyptic number.

It is an amenable number.

21333313 is a deficient number, since it is larger than the sum of its proper divisors (83267).

21333313 is an equidigital number, since it uses as much as digits as its factorization.

21333313 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83266.

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

The square root of 21333313 is about 4618.7999523686. The cubic root of 21333313 is about 277.3444216256.

Adding to 21333313 its reverse (31333312), we get a palindrome (52666625).

Subtracting 21333313 from its reverse (31333312), we obtain a palindrome (9999999).

The spelling of 21333313 in words is "twenty-one million, three hundred thirty-three thousand, three hundred thirteen".