Let's divide 573751 by 21
The aim is to understand the frequency of 21 in 573751.

Let's proceed to step 1:
If we divide 5 by 21, we get 0 and a remainder of 5.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtracting 0 from 5 leaves us with 5.
Take the next digit (7) from the dividend and append it to 5, then repeat: 57 / 21

Step 2:
If we divide 57 by 21, we get 2 and a remainder of 15.
Record the quotient 2 as the next digit in the result. 
Result so far: 2.0
The remainder is 15 after subtracting 42 from 57.
Take the next digit (3) from the dividend and append it to 15, then repeat: 153 / 21

Going ahead to step 3:
21 can be fit into 153 7 times, resulting in a remainder of 6.
Write down 7 as next digit of the result. 
Result so far: 27.0
Subtracting 147 from 153 leaves us with 6.
Fetch the next digit (7) from the dividend, attach it to 6 and continue: 67 / 21

Moving on to step 4:
21 can be fit into 67 3 times, resulting in a remainder of 4.
Record the quotient 3 as the next digit in the result. 
Result so far: 273.0
Subtracting 63 from 67 leaves us with 4.
Grab the next digit (5) from the dividend, add it to 4, then carry on: 45 / 21

Advancing to step 5:
The number 21 fits into 45 2 times, leaving a remainder of 3.
Use 2 as the next digit of our solution. 
Result so far: 2732.0
If we subtract 42 from 45, we get 3.
Grab the next digit (1) from the dividend, add it to 3, then carry on: 31 / 21

Moving on to step 6:
If we divide 31 by 21, we get 1 and a remainder of 10.
The number 1 becomes the next digit in our result. 
Result so far: 27321.0
The remainder is 10 after subtracting 21 from 31.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Advancing to step 7:
100 divided by 21 is 4 with a remainder of 16.
Put 4 as the next digit of the answer. 
Result so far: 27321.4
Subtracting 84 from 100 leaves us with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Let's proceed to step 8:
If we divide 160 by 21, we get 7 and a remainder of 13.
Record the quotient 7 as the next digit in the result. 
Result so far: 27321.47
If we take 147 away from 160, we end up with 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

On to step 9:
When dividing 130 by 21, we get 6 with a remainder of 4.
Write down 6 as next digit of the result. 
Result so far: 27321.476
If we subtract 126 from 130, we get 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Going ahead to step 10:
21 goes into 40 1 times with a remainder of 19.
The number 1 becomes the next digit in our result. 
Result so far: 27321.4761
The remainder is 19 after subtracting 21 from 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Step 11:
The number 21 fits into 190 9 times, leaving a remainder of 1.
Write down 9 as next digit of the result. 
Result so far: 27321.47619
The remainder is 1 after subtracting 189 from 190.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Step 12:
If we divide 10 by 21, we get 0 and a remainder of 10.
Record the quotient 0 as the next digit in the result. 
Result so far: 27321.47619
Subtract 0 from 10 to get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Moving on to step 13:
When dividing 100 by 21, we get 4 with a remainder of 16.
Record the quotient 4 as the next digit in the result. 
Result so far: 27321.4761904
If we subtract 84 from 100, we get 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Going ahead to step 14:
When dividing 160 by 21, we get 7 with a remainder of 13.
The number 7 becomes the next digit in our result. 
Result so far: 27321.47619047
Subtracting 147 from 160 leaves us with 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

The quotient of the division is 27321.47619047, and the remainder is 1.3e-08.