21042233 has 4 divisors (see below), whose sum is σ = 21610980. Its totient is φ = 20473488.

The previous prime is 21042223. The next prime is 21042251. The reversal of 21042233 is 33224012.

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 11075584 + 9966649 = 3328^2 + 3157^2 .

It is a cyclic number.

It is not a de Polignac number, because 21042233 - 2²⁴ = 4265017 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21042223) 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, 284318 + ... + 284391.

It is an arithmetic number, because the mean of its divisors is an integer number (5402745).

Almost surely, 2^21042233 is an apocalyptic number.

It is an amenable number.

21042233 is a deficient number, since it is larger than the sum of its proper divisors (568747).

21042233 is an equidigital number, since it uses as much as digits as its factorization.

21042233 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 568746.

The product of its (nonzero) digits is 288, while the sum is 17.

The square root of 21042233 is about 4587.1813785810. The cubic root of 21042233 is about 276.0772424358.

Adding to 21042233 its reverse (33224012), we get a palindrome (54266245).

The spelling of 21042233 in words is "twenty-one million, forty-two thousand, two hundred thirty-three".