21056233 has 16 divisors (see below), whose sum is σ = 23976000. Its totient is φ = 18316480.

The previous prime is 21056227. The next prime is 21056249. The reversal of 21056233 is 33265012.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21056233 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21056263) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 47310 + ... + 47752.

It is an arithmetic number, because the mean of its divisors is an integer number (1498500).

Almost surely, 2^21056233 is an apocalyptic number.

It is an amenable number.

21056233 is a deficient number, since it is larger than the sum of its proper divisors (2919767).

21056233 is a wasteful number, since it uses less digits than its factorization.

21056233 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 632.

The product of its (nonzero) digits is 1080, while the sum is 22.

The square root of 21056233 is about 4588.7071163891. The cubic root of 21056233 is about 276.1384562263.

It can be divided in two parts, 2105 and 6233, that added together give a palindrome (8338).

The spelling of 21056233 in words is "twenty-one million, fifty-six thousand, two hundred thirty-three".