621291 ÷ 39 
Our goal is to divide 621291 by 39.

Advancing to step 1:
If we divide 6 by 39, we get 0 and a remainder of 6.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 6 to get 6.
Include the next digit (2) from the dividend after 6, then repeat: 62 / 39

Step 2:
62 divided by 39 is 1 with a remainder of 23.
The next digit of our result is 1. 
Result so far: 1.0
If we subtract 39 from 62, we get 23.
Take the next digit (1) from the dividend and append it to 23, then repeat: 231 / 39

On to step 3:
The number 39 fits into 231 5 times, leaving a remainder of 36.
The number 5 becomes the next digit in our result. 
Result so far: 15.0
Deduct 195 from 231 and we're left with 36.
Take the next digit (2) from the dividend and append it to 36, then repeat: 362 / 39

Let's proceed to step 4:
362 divided by 39 is 9 with a remainder of 11.
Use 9 as the next digit of our solution. 
Result so far: 159.0
Subtract 351 from 362 to get 11.
Grab the next digit (9) from the dividend, add it to 11, then carry on: 119 / 39

Step 5:
39 can be fit into 119 3 times, resulting in a remainder of 2.
Write down 3 as next digit of the result. 
Result so far: 1593.0
If we take 117 away from 119, we end up with 2.
Append the next digit (1) from the dividend to 2 and continue with: 21 / 39

Moving on to step 6:
21 divided by 39 is 0 with a remainder of 21.
Record the quotient 0 as the next digit in the result. 
Result so far: 15930.0
Subtract 0 from 21 to get 21.
Since there are no more digits in the dividend, we add a zero to the remainder making it 210, and continue the process.

Let's proceed to step 7:
39 can be fit into 210 5 times, resulting in a remainder of 15.
The next digit of our result is 5. 
Result so far: 15930.5
Subtracting 195 from 210 leaves us with 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Moving on to step 8:
If we divide 150 by 39, we get 3 and a remainder of 33.
The number 3 becomes the next digit in our result. 
Result so far: 15930.53
If we take 117 away from 150, we end up with 33.
Since there are no more digits in the dividend, we add a zero to the remainder making it 330, and continue the process.

Let's proceed to step 9:
When dividing 330 by 39, we get 8 with a remainder of 18.
Put 8 as the next digit of the answer. 
Result so far: 15930.538
If we subtract 312 from 330, we get 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Going ahead to step 10:
If we divide 180 by 39, we get 4 and a remainder of 24.
Write down 4 as next digit of the result. 
Result so far: 15930.5384
The remainder is 24 after subtracting 156 from 180.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

Let's proceed to step 11:
39 can be fit into 240 6 times, resulting in a remainder of 6.
Record the quotient 6 as the next digit in the result. 
Result so far: 15930.53846
Subtract 234 from 240 to get 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Going ahead to step 12:
The number 39 fits into 60 1 times, leaving a remainder of 21.
The next digit of our result is 1. 
Result so far: 15930.538461
Subtracting 39 from 60 leaves us with 21.
Since there are no more digits in the dividend, we add a zero to the remainder making it 210, and continue the process.

Step 13:
39 goes into 210 5 times with a remainder of 15.
Put 5 as the next digit of the answer. 
Result so far: 15930.5384615
Deduct 195 from 210 and we're left with 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Step 14:
The number 39 fits into 150 3 times, leaving a remainder of 33.
The number 3 becomes the next digit in our result. 
Result so far: 15930.53846153
Subtracting 117 from 150 leaves us with 33.
Since there are no more digits in the dividend, we add a zero to the remainder making it 330, and continue the process.

In conclusion, the division gives 15930.53846153 with a balance of 3.3e-08.