86451100 ÷ 621 
We want to figure out the number of times 86451100 can be divided by 621.

Step 1:
If we divide 8 by 621, we get 0 and a remainder of 8.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtracting 0 from 8 leaves us with 8.
Grab the next digit (6) from the dividend, add it to 8, then carry on: 86 / 621

Let's proceed to step 2:
The number 621 fits into 86 0 times, leaving a remainder of 86.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtract 0 from 86 to get 86.
Grab the next digit (4) from the dividend, add it to 86, then carry on: 864 / 621

On to step 3:
621 goes into 864 1 times with a remainder of 243.
Write down 1 as next digit of the result. 
Result so far: 1.0
If we subtract 621 from 864, we get 243.
Append the next digit (5) from the dividend to 243 and continue with: 2435 / 621

Going ahead to step 4:
2435 divided by 621 is 3 with a remainder of 572.
The next digit of our result is 3. 
Result so far: 13.0
Subtracting 1863 from 2435 leaves us with 572.
Bring next digit (1) of the dividend behind the 572 and repeat the process: 5721 / 621

Going ahead to step 5:
621 goes into 5721 9 times with a remainder of 132.
The next digit of our result is 9. 
Result so far: 139.0
Deduct 5589 from 5721 and we're left with 132.
Include the next digit (1) from the dividend after 132, then repeat: 1321 / 621

Going ahead to step 6:
1321 divided by 621 is 2 with a remainder of 79.
Write down 2 as next digit of the result. 
Result so far: 1392.0
If we subtract 1242 from 1321, we get 79.
Take the next digit (0) from the dividend and append it to 79, then repeat: 790 / 621

Going ahead to step 7:
If we divide 790 by 621, we get 1 and a remainder of 169.
Record the quotient 1 as the next digit in the result. 
Result so far: 13921.0
Subtract 621 from 790 to get 169.
Take the next digit (0) from the dividend and append it to 169, then repeat: 1690 / 621

On to step 8:
If we divide 1690 by 621, we get 2 and a remainder of 448.
The next digit of our result is 2. 
Result so far: 139212.0
The remainder is 448 after subtracting 1242 from 1690.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4480, and continue the process.

Moving on to step 9:
If we divide 4480 by 621, we get 7 and a remainder of 133.
Write down 7 as next digit of the result. 
Result so far: 139212.7
The remainder is 133 after subtracting 4347 from 4480.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1330, and continue the process.

Going ahead to step 10:
621 goes into 1330 2 times with a remainder of 88.
Put 2 as the next digit of the answer. 
Result so far: 139212.72
If we take 1242 away from 1330, we end up with 88.
Since there are no more digits in the dividend, we add a zero to the remainder making it 880, and continue the process.

Going ahead to step 11:
If we divide 880 by 621, we get 1 and a remainder of 259.
Use 1 as the next digit of our solution. 
Result so far: 139212.721
Subtracting 621 from 880 leaves us with 259.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2590, and continue the process.

Moving on to step 12:
2590 divided by 621 is 4 with a remainder of 106.
Record the quotient 4 as the next digit in the result. 
Result so far: 139212.7214
Subtract 2484 from 2590 to get 106.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1060, and continue the process.

Let's proceed to step 13:
The number 621 fits into 1060 1 times, leaving a remainder of 439.
Write down 1 as next digit of the result. 
Result so far: 139212.72141
Deduct 621 from 1060 and we're left with 439.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4390, and continue the process.

Step 14:
When dividing 4390 by 621, we get 7 with a remainder of 43.
Put 7 as the next digit of the answer. 
Result so far: 139212.721417
If we subtract 4347 from 4390, we get 43.
Since there are no more digits in the dividend, we add a zero to the remainder making it 430, and continue the process.

Let's proceed to step 15:
621 goes into 430 0 times with a remainder of 430.
Put 0 as the next digit of the answer. 
Result so far: 139212.721417
If we take 0 away from 430, we end up with 430.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4300, and continue the process.

Advancing to step 16:
4300 divided by 621 is 6 with a remainder of 574.
Use 6 as the next digit of our solution. 
Result so far: 139212.72141706
Subtracting 3726 from 4300 leaves us with 574.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5740, and continue the process.

The final result is 139212.72141706 with a remainder of 5.74e-07.