861644 divided by 81 
Let's see how many times 81 fits into 861644.

Advancing to step 1:
If we divide 8 by 81, we get 0 and a remainder of 8.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Deduct 0 from 8 and we're left with 8.
Append the next digit (6) from the dividend to 8 and continue with: 86 / 81

Step 2:
When dividing 86 by 81, we get 1 with a remainder of 5.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
Subtract 81 from 86 to get 5.
Take the next digit (1) from the dividend and append it to 5, then repeat: 51 / 81

Going ahead to step 3:
If we divide 51 by 81, we get 0 and a remainder of 51.
Record the quotient 0 as the next digit in the result. 
Result so far: 10.0
Subtracting 0 from 51 leaves us with 51.
Fetch the next digit (6) from the dividend, attach it to 51 and continue: 516 / 81

Step 4:
81 goes into 516 6 times with a remainder of 30.
Put 6 as the next digit of the answer. 
Result so far: 106.0
If we take 486 away from 516, we end up with 30.
Bring next digit (4) of the dividend behind the 30 and repeat the process: 304 / 81

On to step 5:
When dividing 304 by 81, we get 3 with a remainder of 61.
Use 3 as the next digit of our solution. 
Result so far: 1063.0
Subtracting 243 from 304 leaves us with 61.
Append the next digit (4) from the dividend to 61 and continue with: 614 / 81

On to step 6:
81 can be fit into 614 7 times, resulting in a remainder of 47.
Use 7 as the next digit of our solution. 
Result so far: 10637.0
Deduct 567 from 614 and we're left with 47.
Since there are no more digits in the dividend, we add a zero to the remainder making it 470, and continue the process.

Going ahead to step 7:
81 can be fit into 470 5 times, resulting in a remainder of 65.
Use 5 as the next digit of our solution. 
Result so far: 10637.5
Subtracting 405 from 470 leaves us with 65.
Since there are no more digits in the dividend, we add a zero to the remainder making it 650, and continue the process.

On to step 8:
When dividing 650 by 81, we get 8 with a remainder of 2.
The number 8 becomes the next digit in our result. 
Result so far: 10637.58
Subtract 648 from 650 to get 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Going ahead to step 9:
20 divided by 81 is 0 with a remainder of 20.
Record the quotient 0 as the next digit in the result. 
Result so far: 10637.58
The remainder is 20 after subtracting 0 from 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Step 10:
When dividing 200 by 81, we get 2 with a remainder of 38.
The next digit of our result is 2. 
Result so far: 10637.5802
Subtract 162 from 200 to get 38.
Since there are no more digits in the dividend, we add a zero to the remainder making it 380, and continue the process.

Step 11:
If we divide 380 by 81, we get 4 and a remainder of 56.
The number 4 becomes the next digit in our result. 
Result so far: 10637.58024
Deduct 324 from 380 and we're left with 56.
Since there are no more digits in the dividend, we add a zero to the remainder making it 560, and continue the process.

Going ahead to step 12:
81 can be fit into 560 6 times, resulting in a remainder of 74.
Record the quotient 6 as the next digit in the result. 
Result so far: 10637.580246
The remainder is 74 after subtracting 486 from 560.
Since there are no more digits in the dividend, we add a zero to the remainder making it 740, and continue the process.

Going ahead to step 13:
740 divided by 81 is 9 with a remainder of 11.
Record the quotient 9 as the next digit in the result. 
Result so far: 10637.5802469
Subtracting 729 from 740 leaves us with 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Going ahead to step 14:
81 can be fit into 110 1 times, resulting in a remainder of 29.
Put 1 as the next digit of the answer. 
Result so far: 10637.58024691
Deduct 81 from 110 and we're left with 29.
Since there are no more digits in the dividend, we add a zero to the remainder making it 290, and continue the process.

The final outcome is 10637.58024691, with a leftover of 2.9e-08.