We're dividing 53905073 by 621 
The aim is to understand the frequency of 621 in 53905073.

Step 1:
621 goes into 5 0 times with a remainder of 5.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Deduct 0 from 5 and we're left with 5.
Grab the next digit (3) from the dividend, add it to 5, then carry on: 53 / 621

Step 2:
When dividing 53 by 621, we get 0 with a remainder of 53.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we take 0 away from 53, we end up with 53.
Fetch the next digit (9) from the dividend, attach it to 53 and continue: 539 / 621

Going ahead to step 3:
539 divided by 621 is 0 with a remainder of 539.
Put 0 as the next digit of the answer. 
Result so far: 0.0
The remainder is 539 after subtracting 0 from 539.
Append the next digit (0) from the dividend to 539 and continue with: 5390 / 621

Moving on to step 4:
When dividing 5390 by 621, we get 8 with a remainder of 422.
Record the quotient 8 as the next digit in the result. 
Result so far: 8.0
Deduct 4968 from 5390 and we're left with 422.
Take the next digit (5) from the dividend and append it to 422, then repeat: 4225 / 621

Moving on to step 5:
If we divide 4225 by 621, we get 6 and a remainder of 499.
Write down 6 as next digit of the result. 
Result so far: 86.0
Subtracting 3726 from 4225 leaves us with 499.
Bring next digit (0) of the dividend behind the 499 and repeat the process: 4990 / 621

Going ahead to step 6:
621 goes into 4990 8 times with a remainder of 22.
Put 8 as the next digit of the answer. 
Result so far: 868.0
If we subtract 4968 from 4990, we get 22.
Bring next digit (7) of the dividend behind the 22 and repeat the process: 227 / 621

Let's proceed to step 7:
If we divide 227 by 621, we get 0 and a remainder of 227.
Put 0 as the next digit of the answer. 
Result so far: 8680.0
Deduct 0 from 227 and we're left with 227.
Append the next digit (3) from the dividend to 227 and continue with: 2273 / 621

On to step 8:
The number 621 fits into 2273 3 times, leaving a remainder of 410.
Write down 3 as next digit of the result. 
Result so far: 86803.0
Subtract 1863 from 2273 to get 410.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4100, and continue the process.

On to step 9:
If we divide 4100 by 621, we get 6 and a remainder of 374.
Use 6 as the next digit of our solution. 
Result so far: 86803.6
Subtract 3726 from 4100 to get 374.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3740, and continue the process.

On to step 10:
If we divide 3740 by 621, we get 6 and a remainder of 14.
Record the quotient 6 as the next digit in the result. 
Result so far: 86803.66
The remainder is 14 after subtracting 3726 from 3740.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

In conclusion, the division gives 86803.66 with a balance of 0.014.