972864 divided by 21 
We're looking to find how many times 21 goes into 972864.

Going ahead to step 1:
When dividing 9 by 21, we get 0 with a remainder of 9.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 9 to get 9.
Grab the next digit (7) from the dividend, add it to 9, then carry on: 97 / 21

Moving on to step 2:
21 goes into 97 4 times with a remainder of 13.
Write down 4 as next digit of the result. 
Result so far: 4.0
If we take 84 away from 97, we end up with 13.
Append the next digit (2) from the dividend to 13 and continue with: 132 / 21

On to step 3:
When dividing 132 by 21, we get 6 with a remainder of 6.
The next digit of our result is 6. 
Result so far: 46.0
Subtract 126 from 132 to get 6.
Fetch the next digit (8) from the dividend, attach it to 6 and continue: 68 / 21

Step 4:
21 can be fit into 68 3 times, resulting in a remainder of 5.
The next digit of our result is 3. 
Result so far: 463.0
Deduct 63 from 68 and we're left with 5.
Bring next digit (6) of the dividend behind the 5 and repeat the process: 56 / 21

Going ahead to step 5:
56 divided by 21 is 2 with a remainder of 14.
Write down 2 as next digit of the result. 
Result so far: 4632.0
If we subtract 42 from 56, we get 14.
Include the next digit (4) from the dividend after 14, then repeat: 144 / 21

On to step 6:
144 divided by 21 is 6 with a remainder of 18.
Record the quotient 6 as the next digit in the result. 
Result so far: 46326.0
Subtract 126 from 144 to get 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Step 7:
When dividing 180 by 21, we get 8 with a remainder of 12.
Record the quotient 8 as the next digit in the result. 
Result so far: 46326.8
Subtracting 168 from 180 leaves us with 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

On to step 8:
If we divide 120 by 21, we get 5 and a remainder of 15.
Put 5 as the next digit of the answer. 
Result so far: 46326.85
If we take 105 away from 120, we end up with 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

On to step 9:
21 goes into 150 7 times with a remainder of 3.
The next digit of our result is 7. 
Result so far: 46326.857
If we take 147 away from 150, we end up with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Step 10:
21 goes into 30 1 times with a remainder of 9.
The number 1 becomes the next digit in our result. 
Result so far: 46326.8571
Deduct 21 from 30 and we're left with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Let's proceed to step 11:
21 goes into 90 4 times with a remainder of 6.
Use 4 as the next digit of our solution. 
Result so far: 46326.85714
If we subtract 84 from 90, we get 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Let's proceed to step 12:
60 divided by 21 is 2 with a remainder of 18.
Record the quotient 2 as the next digit in the result. 
Result so far: 46326.857142
If we subtract 42 from 60, we get 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Advancing to step 13:
21 can be fit into 180 8 times, resulting in a remainder of 12.
Use 8 as the next digit of our solution. 
Result so far: 46326.8571428
If we take 168 away from 180, we end up with 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Advancing to step 14:
120 divided by 21 is 5 with a remainder of 15.
Put 5 as the next digit of the answer. 
Result so far: 46326.85714285
Subtract 105 from 120 to get 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Our division results in 46326.85714285 with a remaining 1.5e-08.