21128233 has 8 divisors (see below), whose sum is σ = 24368960. Its totient is φ = 17943120.

The previous prime is 21128213. The next prime is 21128257. The reversal of 21128233 is 33282112.

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 21128233 - 2⁵ = 21128201 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21128203) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13083 + ... + 14608.

It is an arithmetic number, because the mean of its divisors is an integer number (3046120).

Almost surely, 2^21128233 is an apocalyptic number.

It is an amenable number.

21128233 is a deficient number, since it is larger than the sum of its proper divisors (3240727).

21128233 is a wasteful number, since it uses less digits than its factorization.

21128233 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27807.

The product of its digits is 576, while the sum is 22.

The square root of 21128233 is about 4596.5457682917. The cubic root of 21128233 is about 276.4528421571.

The spelling of 21128233 in words is "twenty-one million, one hundred twenty-eight thousand, two hundred thirty-three".