We look at the division of 521171 by 64 
The aim is to understand the frequency of 64 in 521171.

On to step 1:
When dividing 5 by 64, we get 0 with a remainder of 5.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 5 to get 5.
Take the next digit (2) from the dividend and append it to 5, then repeat: 52 / 64

On to step 2:
64 goes into 52 0 times with a remainder of 52.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtracting 0 from 52 leaves us with 52.
Take the next digit (1) from the dividend and append it to 52, then repeat: 521 / 64

On to step 3:
64 goes into 521 8 times with a remainder of 9.
Put 8 as the next digit of the answer. 
Result so far: 8.0
Deduct 512 from 521 and we're left with 9.
Include the next digit (1) from the dividend after 9, then repeat: 91 / 64

Moving on to step 4:
64 can be fit into 91 1 times, resulting in a remainder of 27.
Record the quotient 1 as the next digit in the result. 
Result so far: 81.0
If we subtract 64 from 91, we get 27.
Bring next digit (7) of the dividend behind the 27 and repeat the process: 277 / 64

On to step 5:
64 goes into 277 4 times with a remainder of 21.
The next digit of our result is 4. 
Result so far: 814.0
The remainder is 21 after subtracting 256 from 277.
Take the next digit (1) from the dividend and append it to 21, then repeat: 211 / 64

Advancing to step 6:
If we divide 211 by 64, we get 3 and a remainder of 19.
The next digit of our result is 3. 
Result so far: 8143.0
Subtract 192 from 211 to get 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 7:
64 goes into 190 2 times with a remainder of 62.
Put 2 as the next digit of the answer. 
Result so far: 8143.2
The remainder is 62 after subtracting 128 from 190.
Since there are no more digits in the dividend, we add a zero to the remainder making it 620, and continue the process.

Let's proceed to step 8:
If we divide 620 by 64, we get 9 and a remainder of 44.
Use 9 as the next digit of our solution. 
Result so far: 8143.29
If we take 576 away from 620, we end up with 44.
Since there are no more digits in the dividend, we add a zero to the remainder making it 440, and continue the process.

Moving on to step 9:
64 can be fit into 440 6 times, resulting in a remainder of 56.
Record the quotient 6 as the next digit in the result. 
Result so far: 8143.296
If we take 384 away from 440, we end up with 56.
Since there are no more digits in the dividend, we add a zero to the remainder making it 560, and continue the process.

Step 10:
64 goes into 560 8 times with a remainder of 48.
Write down 8 as next digit of the result. 
Result so far: 8143.2968
If we take 512 away from 560, we end up with 48.
Since there are no more digits in the dividend, we add a zero to the remainder making it 480, and continue the process.

On to step 11:
64 can be fit into 480 7 times, resulting in a remainder of 32.
The number 7 becomes the next digit in our result. 
Result so far: 8143.29687
Subtract 448 from 480 to get 32.
Since there are no more digits in the dividend, we add a zero to the remainder making it 320, and continue the process.

Moving on to step 12:
When dividing 320 by 64, we get 5 with a remainder of 0.
The number 5 becomes the next digit in our result. 
Result so far: 8143.296875
If we take 320 away from 320, we end up with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Going ahead to step 13:
When dividing 0 by 64, we get 0 with a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 8143.296875
Subtracting 0 from 0 leaves us with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Going ahead to step 14:
When dividing 0 by 64, we get 0 with a remainder of 0.
The next digit of our result is 0. 
Result so far: 8143.296875
Subtracting 0 from 0 leaves us with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

After the division, we end up with 8143.296875 and a remainder of 0.0.