643779 divided by 39 
We want to figure out the number of times 643779 can be divided by 39.

On to step 1:
If we divide 6 by 39, we get 0 and a remainder of 6.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 6, we get 6.
Grab the next digit (4) from the dividend, add it to 6, then carry on: 64 / 39

Let's proceed to step 2:
When dividing 64 by 39, we get 1 with a remainder of 25.
Use 1 as the next digit of our solution. 
Result so far: 1.0
The remainder is 25 after subtracting 39 from 64.
Append the next digit (3) from the dividend to 25 and continue with: 253 / 39

Let's proceed to step 3:
When dividing 253 by 39, we get 6 with a remainder of 19.
Write down 6 as next digit of the result. 
Result so far: 16.0
If we take 234 away from 253, we end up with 19.
Bring next digit (7) of the dividend behind the 19 and repeat the process: 197 / 39

Going ahead to step 4:
The number 39 fits into 197 5 times, leaving a remainder of 2.
Use 5 as the next digit of our solution. 
Result so far: 165.0
Subtracting 195 from 197 leaves us with 2.
Take the next digit (7) from the dividend and append it to 2, then repeat: 27 / 39

Moving on to step 5:
39 goes into 27 0 times with a remainder of 27.
The next digit of our result is 0. 
Result so far: 1650.0
If we subtract 0 from 27, we get 27.
Grab the next digit (9) from the dividend, add it to 27, then carry on: 279 / 39

On to step 6:
39 goes into 279 7 times with a remainder of 6.
Use 7 as the next digit of our solution. 
Result so far: 16507.0
Subtracting 273 from 279 leaves us with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Advancing to step 7:
The number 39 fits into 60 1 times, leaving a remainder of 21.
Put 1 as the next digit of the answer. 
Result so far: 16507.1
If we subtract 39 from 60, we 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 8:
39 goes into 210 5 times with a remainder of 15.
Use 5 as the next digit of our solution. 
Result so far: 16507.15
Subtract 195 from 210 to get 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 9:
39 goes into 150 3 times with a remainder of 33.
Write down 3 as next digit of the result. 
Result so far: 16507.153
If we subtract 117 from 150, we get 33.
Since there are no more digits in the dividend, we add a zero to the remainder making it 330, and continue the process.

Moving on to step 10:
39 goes into 330 8 times with a remainder of 18.
Record the quotient 8 as the next digit in the result. 
Result so far: 16507.1538
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.

Moving on to step 11:
39 can be fit into 180 4 times, resulting in a remainder of 24.
Record the quotient 4 as the next digit in the result. 
Result so far: 16507.15384
If we subtract 156 from 180, we get 24.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

Step 12:
39 can be fit into 240 6 times, resulting in a remainder of 6.
The number 6 becomes the next digit in our result. 
Result so far: 16507.153846
Subtracting 234 from 240 leaves us with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Step 13:
39 goes into 60 1 times with a remainder of 21.
Put 1 as the next digit of the answer. 
Result so far: 16507.1538461
Deduct 39 from 60 and we're left 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 14:
39 can be fit into 210 5 times, resulting in a remainder of 15.
Record the quotient 5 as the next digit in the result. 
Result so far: 16507.15384615
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.

In conclusion, the division gives 16507.15384615 with a balance of 1.5e-08.