We look at the division of 81391609 by 666 
We want to divide 81391609 by 666.

On to step 1:
When dividing 8 by 666, we get 0 with a remainder of 8.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 8 after subtracting 0 from 8.
Include the next digit (1) from the dividend after 8, then repeat: 81 / 666

Step 2:
666 goes into 81 0 times with a remainder of 81.
Put 0 as the next digit of the answer. 
Result so far: 0.0
The remainder is 81 after subtracting 0 from 81.
Take the next digit (3) from the dividend and append it to 81, then repeat: 813 / 666

On to step 3:
When dividing 813 by 666, we get 1 with a remainder of 147.
The number 1 becomes the next digit in our result. 
Result so far: 1.0
Subtract 666 from 813 to get 147.
Fetch the next digit (9) from the dividend, attach it to 147 and continue: 1479 / 666

Going ahead to step 4:
If we divide 1479 by 666, we get 2 and a remainder of 147.
Use 2 as the next digit of our solution. 
Result so far: 12.0
If we take 1332 away from 1479, we end up with 147.
Append the next digit (1) from the dividend to 147 and continue with: 1471 / 666

Moving on to step 5:
If we divide 1471 by 666, we get 2 and a remainder of 139.
Use 2 as the next digit of our solution. 
Result so far: 122.0
Deduct 1332 from 1471 and we're left with 139.
Bring next digit (6) of the dividend behind the 139 and repeat the process: 1396 / 666

Let's proceed to step 6:
If we divide 1396 by 666, we get 2 and a remainder of 64.
Use 2 as the next digit of our solution. 
Result so far: 1222.0
Subtracting 1332 from 1396 leaves us with 64.
Grab the next digit (0) from the dividend, add it to 64, then carry on: 640 / 666

On to step 7:
666 can be fit into 640 0 times, resulting in a remainder of 640.
Use 0 as the next digit of our solution. 
Result so far: 12220.0
Deduct 0 from 640 and we're left with 640.
Grab the next digit (9) from the dividend, add it to 640, then carry on: 6409 / 666

Advancing to step 8:
When dividing 6409 by 666, we get 9 with a remainder of 415.
Put 9 as the next digit of the answer. 
Result so far: 122209.0
Subtract 5994 from 6409 to get 415.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4150, and continue the process.

Step 9:
If we divide 4150 by 666, we get 6 and a remainder of 154.
Record the quotient 6 as the next digit in the result. 
Result so far: 122209.6
Deduct 3996 from 4150 and we're left with 154.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1540, and continue the process.

Let's proceed to step 10:
666 can be fit into 1540 2 times, resulting in a remainder of 208.
The next digit of our result is 2. 
Result so far: 122209.62
The remainder is 208 after subtracting 1332 from 1540.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2080, and continue the process.

On to step 11:
2080 divided by 666 is 3 with a remainder of 82.
The number 3 becomes the next digit in our result. 
Result so far: 122209.623
If we subtract 1998 from 2080, we get 82.
Since there are no more digits in the dividend, we add a zero to the remainder making it 820, and continue the process.

On to step 12:
When dividing 820 by 666, we get 1 with a remainder of 154.
The number 1 becomes the next digit in our result. 
Result so far: 122209.6231
If we take 666 away from 820, we end up with 154.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1540, and continue the process.

Going ahead to step 13:
666 goes into 1540 2 times with a remainder of 208.
Use 2 as the next digit of our solution. 
Result so far: 122209.62312
Subtracting 1332 from 1540 leaves us with 208.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2080, and continue the process.

Advancing to step 14:
If we divide 2080 by 666, we get 3 and a remainder of 82.
Put 3 as the next digit of the answer. 
Result so far: 122209.623123
The remainder is 82 after subtracting 1998 from 2080.
Since there are no more digits in the dividend, we add a zero to the remainder making it 820, and continue the process.

Going ahead to step 15:
When dividing 820 by 666, we get 1 with a remainder of 154.
Put 1 as the next digit of the answer. 
Result so far: 122209.6231231
Subtracting 666 from 820 leaves us with 154.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1540, and continue the process.

Step 16:
666 goes into 1540 2 times with a remainder of 208.
Record the quotient 2 as the next digit in the result. 
Result so far: 122209.62312312
Subtracting 1332 from 1540 leaves us with 208.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2080, and continue the process.

The final result is 122209.62312312 with a remainder of 2.08e-07.