81876586 divided by 21 
Our goal is to divide 81876586 by 21.

Advancing to step 1:
8 divided by 21 is 0 with a remainder of 8.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we subtract 0 from 8, we get 8.
Bring next digit (1) of the dividend behind the 8 and repeat the process: 81 / 21

On to step 2:
If we divide 81 by 21, we get 3 and a remainder of 18.
Use 3 as the next digit of our solution. 
Result so far: 3.0
Subtracting 63 from 81 leaves us with 18.
Take the next digit (8) from the dividend and append it to 18, then repeat: 188 / 21

Moving on to step 3:
21 goes into 188 8 times with a remainder of 20.
Record the quotient 8 as the next digit in the result. 
Result so far: 38.0
Subtract 168 from 188 to get 20.
Grab the next digit (7) from the dividend, add it to 20, then carry on: 207 / 21

Step 4:
If we divide 207 by 21, we get 9 and a remainder of 18.
Use 9 as the next digit of our solution. 
Result so far: 389.0
Subtract 189 from 207 to get 18.
Include the next digit (6) from the dividend after 18, then repeat: 186 / 21

Going ahead to step 5:
If we divide 186 by 21, we get 8 and a remainder of 18.
Write down 8 as next digit of the result. 
Result so far: 3898.0
Deduct 168 from 186 and we're left with 18.
Bring next digit (5) of the dividend behind the 18 and repeat the process: 185 / 21

Going ahead to step 6:
The number 21 fits into 185 8 times, leaving a remainder of 17.
Use 8 as the next digit of our solution. 
Result so far: 38988.0
Subtracting 168 from 185 leaves us with 17.
Grab the next digit (8) from the dividend, add it to 17, then carry on: 178 / 21

On to step 7:
21 can be fit into 178 8 times, resulting in a remainder of 10.
The next digit of our result is 8. 
Result so far: 389888.0
If we subtract 168 from 178, we get 10.
Fetch the next digit (6) from the dividend, attach it to 10 and continue: 106 / 21

On to step 8:
The number 21 fits into 106 5 times, leaving a remainder of 1.
Use 5 as the next digit of our solution. 
Result so far: 3898885.0
Deduct 105 from 106 and we're left with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Let's proceed to step 9:
21 can be fit into 10 0 times, resulting in a remainder of 10.
Write down 0 as next digit of the result. 
Result so far: 3898885.0
Subtracting 0 from 10 leaves us with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Advancing to step 10:
21 goes into 100 4 times with a remainder of 16.
The number 4 becomes the next digit in our result. 
Result so far: 3898885.04
If we take 84 away from 100, we end up with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Moving on to step 11:
When dividing 160 by 21, we get 7 with a remainder of 13.
Use 7 as the next digit of our solution. 
Result so far: 3898885.047
Subtract 147 from 160 to get 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Moving on to step 12:
The number 21 fits into 130 6 times, leaving a remainder of 4.
Record the quotient 6 as the next digit in the result. 
Result so far: 3898885.0476
If we subtract 126 from 130, we get 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Let's proceed to step 13:
40 divided by 21 is 1 with a remainder of 19.
Put 1 as the next digit of the answer. 
Result so far: 3898885.04761
Subtracting 21 from 40 leaves us with 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Step 14:
21 goes into 190 9 times with a remainder of 1.
Use 9 as the next digit of our solution. 
Result so far: 3898885.047619
Deduct 189 from 190 and we're left with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Let's proceed to step 15:
If we divide 10 by 21, we get 0 and a remainder of 10.
Record the quotient 0 as the next digit in the result. 
Result so far: 3898885.047619
If we subtract 0 from 10, we get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Step 16:
When dividing 100 by 21, we get 4 with a remainder of 16.
Use 4 as the next digit of our solution. 
Result so far: 3898885.04761904
Deduct 84 from 100 and we're left with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

The quotient of the division is 3898885.04761904, and the remainder is 1.6e-08.