21666231 divided by 865 
We want to figure out the number of times 21666231 can be divided by 865.

Moving on to step 1:
865 can be fit into 2 0 times, resulting in a remainder of 2.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 2, we get 2.
Fetch the next digit (1) from the dividend, attach it to 2 and continue: 21 / 865

Let's proceed to step 2:
When dividing 21 by 865, we get 0 with a remainder of 21.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 21, we get 21.
Include the next digit (6) from the dividend after 21, then repeat: 216 / 865

On to step 3:
The number 865 fits into 216 0 times, leaving a remainder of 216.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Deduct 0 from 216 and we're left with 216.
Take the next digit (6) from the dividend and append it to 216, then repeat: 2166 / 865

On to step 4:
865 can be fit into 2166 2 times, resulting in a remainder of 436.
Write down 2 as next digit of the result. 
Result so far: 2.0
If we subtract 1730 from 2166, we get 436.
Append the next digit (6) from the dividend to 436 and continue with: 4366 / 865

On to step 5:
The number 865 fits into 4366 5 times, leaving a remainder of 41.
Put 5 as the next digit of the answer. 
Result so far: 25.0
The remainder is 41 after subtracting 4325 from 4366.
Take the next digit (2) from the dividend and append it to 41, then repeat: 412 / 865

On to step 6:
865 can be fit into 412 0 times, resulting in a remainder of 412.
The number 0 becomes the next digit in our result. 
Result so far: 250.0
If we subtract 0 from 412, we get 412.
Grab the next digit (3) from the dividend, add it to 412, then carry on: 4123 / 865

Moving on to step 7:
865 can be fit into 4123 4 times, resulting in a remainder of 663.
Write down 4 as next digit of the result. 
Result so far: 2504.0
Deduct 3460 from 4123 and we're left with 663.
Grab the next digit (1) from the dividend, add it to 663, then carry on: 6631 / 865

On to step 8:
6631 divided by 865 is 7 with a remainder of 576.
Write down 7 as next digit of the result. 
Result so far: 25047.0
Subtracting 6055 from 6631 leaves us with 576.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5760, and continue the process.

On to step 9:
865 goes into 5760 6 times with a remainder of 570.
Put 6 as the next digit of the answer. 
Result so far: 25047.6
Deduct 5190 from 5760 and we're left with 570.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5700, and continue the process.

Step 10:
The number 865 fits into 5700 6 times, leaving a remainder of 510.
The number 6 becomes the next digit in our result. 
Result so far: 25047.66
If we subtract 5190 from 5700, we get 510.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5100, and continue the process.

Our division results in 25047.66 with a remaining 0.51.