We look at the division of 36507879 by 721 
The aim is to understand the frequency of 721 in 36507879.

On to step 1:
721 can be fit into 3 0 times, resulting in a remainder of 3.
The next digit of our result is 0. 
Result so far: 0.0
If we subtract 0 from 3, we get 3.
Append the next digit (6) from the dividend to 3 and continue with: 36 / 721

Advancing to step 2:
721 can be fit into 36 0 times, resulting in a remainder of 36.
Write down 0 as next digit of the result. 
Result so far: 0.0
The remainder is 36 after subtracting 0 from 36.
Include the next digit (5) from the dividend after 36, then repeat: 365 / 721

Let's proceed to step 3:
721 goes into 365 0 times with a remainder of 365.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 365, we get 365.
Include the next digit (0) from the dividend after 365, then repeat: 3650 / 721

On to step 4:
721 can be fit into 3650 5 times, resulting in a remainder of 45.
Put 5 as the next digit of the answer. 
Result so far: 5.0
The remainder is 45 after subtracting 3605 from 3650.
Grab the next digit (7) from the dividend, add it to 45, then carry on: 457 / 721

On to step 5:
721 can be fit into 457 0 times, resulting in a remainder of 457.
Write down 0 as next digit of the result. 
Result so far: 50.0
Subtracting 0 from 457 leaves us with 457.
Append the next digit (8) from the dividend to 457 and continue with: 4578 / 721

Step 6:
4578 divided by 721 is 6 with a remainder of 252.
Use 6 as the next digit of our solution. 
Result so far: 506.0
Deduct 4326 from 4578 and we're left with 252.
Grab the next digit (7) from the dividend, add it to 252, then carry on: 2527 / 721

Step 7:
721 goes into 2527 3 times with a remainder of 364.
Use 3 as the next digit of our solution. 
Result so far: 5063.0
Deduct 2163 from 2527 and we're left with 364.
Include the next digit (9) from the dividend after 364, then repeat: 3649 / 721

Going ahead to step 8:
721 goes into 3649 5 times with a remainder of 44.
Put 5 as the next digit of the answer. 
Result so far: 50635.0
The remainder is 44 after subtracting 3605 from 3649.
Since there are no more digits in the dividend, we add a zero to the remainder making it 440, and continue the process.

Step 9:
The number 721 fits into 440 0 times, leaving a remainder of 440.
Write down 0 as next digit of the result. 
Result so far: 50635.0
Deduct 0 from 440 and we're left with 440.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4400, and continue the process.

Let's proceed to step 10:
721 goes into 4400 6 times with a remainder of 74.
The number 6 becomes the next digit in our result. 
Result so far: 50635.06
If we subtract 4326 from 4400, we get 74.
Since there are no more digits in the dividend, we add a zero to the remainder making it 740, and continue the process.

On to step 11:
The number 721 fits into 740 1 times, leaving a remainder of 19.
Record the quotient 1 as the next digit in the result. 
Result so far: 50635.061
If we take 721 away from 740, we end up with 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Advancing to step 12:
When dividing 190 by 721, we get 0 with a remainder of 190.
Use 0 as the next digit of our solution. 
Result so far: 50635.061
Subtract 0 from 190 to get 190.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1900, and continue the process.

Moving on to step 13:
The number 721 fits into 1900 2 times, leaving a remainder of 458.
The number 2 becomes the next digit in our result. 
Result so far: 50635.06102
Subtract 1442 from 1900 to get 458.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4580, and continue the process.

Step 14:
4580 divided by 721 is 6 with a remainder of 254.
Record the quotient 6 as the next digit in the result. 
Result so far: 50635.061026
Subtract 4326 from 4580 to get 254.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2540, and continue the process.

Advancing to step 15:
If we divide 2540 by 721, we get 3 and a remainder of 377.
Record the quotient 3 as the next digit in the result. 
Result so far: 50635.0610263
If we take 2163 away from 2540, we end up with 377.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3770, and continue the process.

Advancing to step 16:
When dividing 3770 by 721, we get 5 with a remainder of 165.
Use 5 as the next digit of our solution. 
Result so far: 50635.06102635
Deduct 3605 from 3770 and we're left with 165.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1650, and continue the process.

After the division, we end up with 50635.06102635 and a remainder of 1.65e-07.