We divide 86100707 by 21
We're looking to find how many times 21 goes into 86100707.

Moving on to step 1:
21 can be fit into 8 0 times, resulting in a remainder of 8.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtracting 0 from 8 leaves us with 8.
Append the next digit (6) from the dividend to 8 and continue with: 86 / 21

Step 2:
21 can be fit into 86 4 times, resulting in a remainder of 2.
Write down 4 as next digit of the result. 
Result so far: 4.0
If we take 84 away from 86, we end up with 2.
Take the next digit (1) from the dividend and append it to 2, then repeat: 21 / 21

Advancing to step 3:
If we divide 21 by 21, we get 1 and a remainder of 0.
Record the quotient 1 as the next digit in the result. 
Result so far: 41.0
If we take 21 away from 21, we end up with 0.
Take the next digit (0) from the dividend and append it to 0, then repeat: 0 / 21

Advancing to step 4:
21 goes into 0 0 times with a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 410.0
Deduct 0 from 0 and we're left with 0.
Append the next digit (0) from the dividend to 0 and continue with: 0 / 21

Advancing to step 5:
0 divided by 21 is 0 with a remainder of 0.
The next digit of our result is 0. 
Result so far: 4100.0
If we take 0 away from 0, we end up with 0.
Include the next digit (7) from the dividend after 0, then repeat: 7 / 21

Going ahead to step 6:
When dividing 7 by 21, we get 0 with a remainder of 7.
The number 0 becomes the next digit in our result. 
Result so far: 41000.0
The remainder is 7 after subtracting 0 from 7.
Include the next digit (0) from the dividend after 7, then repeat: 70 / 21

Going ahead to step 7:
If we divide 70 by 21, we get 3 and a remainder of 7.
Put 3 as the next digit of the answer. 
Result so far: 410003.0
Subtract 63 from 70 to get 7.
Append the next digit (7) from the dividend to 7 and continue with: 77 / 21

Moving on to step 8:
21 can be fit into 77 3 times, resulting in a remainder of 14.
The next digit of our result is 3. 
Result so far: 4100033.0
If we subtract 63 from 77, we get 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

Going ahead to step 9:
21 can be fit into 140 6 times, resulting in a remainder of 14.
Use 6 as the next digit of our solution. 
Result so far: 4100033.6
The remainder is 14 after subtracting 126 from 140.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

Step 10:
21 can be fit into 140 6 times, resulting in a remainder of 14.
Put 6 as the next digit of the answer. 
Result so far: 4100033.66
Subtracting 126 from 140 leaves us with 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

In conclusion, the division gives 4100033.66 with a balance of 0.014.