21228933 has 8 divisors (see below), whose sum is σ = 30878496. Its totient is φ = 12866000.

The previous prime is 21228901. The next prime is 21228953. The reversal of 21228933 is 33982212.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21228933 - 2⁵ = 21228901 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21228933.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21228953) 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 7 ways as a sum of consecutive naturals, for example, 321618 + ... + 321683.

It is an arithmetic number, because the mean of its divisors is an integer number (3859812).

Almost surely, 2^21228933 is an apocalyptic number.

It is an amenable number.

21228933 is a deficient number, since it is larger than the sum of its proper divisors (9649563).

21228933 is a wasteful number, since it uses less digits than its factorization.

21228933 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 643315.

The product of its digits is 5184, while the sum is 30.

The square root of 21228933 is about 4607.4866250484. The cubic root of 21228933 is about 276.8913500392.

The spelling of 21228933 in words is "twenty-one million, two hundred twenty-eight thousand, nine hundred thirty-three".