21668333 has 4 divisors (see below), whose sum is σ = 21715200. Its totient is φ = 21621468.

The previous prime is 21668327. The next prime is 21668389. The reversal of 21668333 is 33386612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21668333 - 2¹⁰ = 21667309 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21668333.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21668033) 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 in 3 ways as a sum of consecutive naturals, for example, 22733 + ... + 23666.

It is an arithmetic number, because the mean of its divisors is an integer number (5428800).

Almost surely, 2^21668333 is an apocalyptic number.

It is an amenable number.

21668333 is a deficient number, since it is larger than the sum of its proper divisors (46867).

21668333 is an equidigital number, since it uses as much as digits as its factorization.

21668333 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46866.

The product of its digits is 15552, while the sum is 32.

The square root of 21668333 is about 4654.9256707277. The cubic root of 21668333 is about 278.7887002111.

The spelling of 21668333 in words is "twenty-one million, six hundred sixty-eight thousand, three hundred thirty-three".