We're dividing 4160049 by 21 
The aim is to understand the frequency of 21 in 4160049.

On to step 1:
When dividing 4 by 21, we get 0 with a remainder of 4.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Deduct 0 from 4 and we're left with 4.
Fetch the next digit (1) from the dividend, attach it to 4 and continue: 41 / 21

On to step 2:
41 divided by 21 is 1 with a remainder of 20.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
Subtracting 21 from 41 leaves us with 20.
Fetch the next digit (6) from the dividend, attach it to 20 and continue: 206 / 21

On to step 3:
21 goes into 206 9 times with a remainder of 17.
The next digit of our result is 9. 
Result so far: 19.0
Subtracting 189 from 206 leaves us with 17.
Append the next digit (0) from the dividend to 17 and continue with: 170 / 21

Step 4:
21 goes into 170 8 times with a remainder of 2.
The number 8 becomes the next digit in our result. 
Result so far: 198.0
If we subtract 168 from 170, we get 2.
Fetch the next digit (0) from the dividend, attach it to 2 and continue: 20 / 21

Moving on to step 5:
21 goes into 20 0 times with a remainder of 20.
Write down 0 as next digit of the result. 
Result so far: 1980.0
If we take 0 away from 20, we end up with 20.
Include the next digit (4) from the dividend after 20, then repeat: 204 / 21

Advancing to step 6:
If we divide 204 by 21, we get 9 and a remainder of 15.
Put 9 as the next digit of the answer. 
Result so far: 19809.0
Subtract 189 from 204 to get 15.
Fetch the next digit (9) from the dividend, attach it to 15 and continue: 159 / 21

Step 7:
21 can be fit into 159 7 times, resulting in a remainder of 12.
Write down 7 as next digit of the result. 
Result so far: 198097.0
Subtract 147 from 159 to get 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Let's proceed to step 8:
120 divided by 21 is 5 with a remainder of 15.
Use 5 as the next digit of our solution. 
Result so far: 198097.5
Deduct 105 from 120 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 9:
150 divided by 21 is 7 with a remainder of 3.
The next digit of our result is 7. 
Result so far: 198097.57
If we take 147 away from 150, we end up with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

On to step 10:
21 goes into 30 1 times with a remainder of 9.
Use 1 as the next digit of our solution. 
Result so far: 198097.571
Subtract 21 from 30 to get 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Let's proceed to step 11:
21 can be fit into 90 4 times, resulting in a remainder of 6.
Use 4 as the next digit of our solution. 
Result so far: 198097.5714
The remainder is 6 after subtracting 84 from 90.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Moving on to step 12:
When dividing 60 by 21, we get 2 with a remainder of 18.
Use 2 as the next digit of our solution. 
Result so far: 198097.57142
If we take 42 away from 60, we end up with 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 13:
21 can be fit into 180 8 times, resulting in a remainder of 12.
Record the quotient 8 as the next digit in the result. 
Result so far: 198097.571428
Subtracting 168 from 180 leaves us with 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Step 14:
When dividing 120 by 21, we get 5 with a remainder of 15.
The next digit of our result is 5. 
Result so far: 198097.5714285
The remainder is 15 after subtracting 105 from 120.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Step 15:
The number 21 fits into 150 7 times, leaving a remainder of 3.
The next digit of our result is 7. 
Result so far: 198097.57142857
Deduct 147 from 150 and we're left with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

The final result is 198097.57142857 with a remainder of 3e-09.