21586799 ÷ 21 
The aim is to understand the frequency of 21 in 21586799.

Going ahead to step 1:
21 goes into 2 0 times with a remainder of 2.
The next digit of our result is 0. 
Result so far: 0.0
If we take 0 away from 2, we end up with 2.
Bring next digit (1) of the dividend behind the 2 and repeat the process: 21 / 21

Advancing to step 2:
21 divided by 21 is 1 with a remainder of 0.
Write down 1 as next digit of the result. 
Result so far: 1.0
Deduct 21 from 21 and we're left with 0.
Append the next digit (5) from the dividend to 0 and continue with: 5 / 21

Let's proceed to step 3:
5 divided by 21 is 0 with a remainder of 5.
Put 0 as the next digit of the answer. 
Result so far: 10.0
Subtracting 0 from 5 leaves us with 5.
Grab the next digit (8) from the dividend, add it to 5, then carry on: 58 / 21

Moving on to step 4:
21 can be fit into 58 2 times, resulting in a remainder of 16.
Write down 2 as next digit of the result. 
Result so far: 102.0
Deduct 42 from 58 and we're left with 16.
Append the next digit (6) from the dividend to 16 and continue with: 166 / 21

Moving on to step 5:
21 goes into 166 7 times with a remainder of 19.
The number 7 becomes the next digit in our result. 
Result so far: 1027.0
Deduct 147 from 166 and we're left with 19.
Take the next digit (7) from the dividend and append it to 19, then repeat: 197 / 21

On to step 6:
When dividing 197 by 21, we get 9 with a remainder of 8.
The number 9 becomes the next digit in our result. 
Result so far: 10279.0
The remainder is 8 after subtracting 189 from 197.
Bring next digit (9) of the dividend behind the 8 and repeat the process: 89 / 21

Moving on to step 7:
21 goes into 89 4 times with a remainder of 5.
Use 4 as the next digit of our solution. 
Result so far: 102794.0
If we subtract 84 from 89, we get 5.
Bring next digit (9) of the dividend behind the 5 and repeat the process: 59 / 21

Advancing to step 8:
21 can be fit into 59 2 times, resulting in a remainder of 17.
Use 2 as the next digit of our solution. 
Result so far: 1027942.0
If we subtract 42 from 59, we get 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Going ahead to step 9:
When dividing 170 by 21, we get 8 with a remainder of 2.
Write down 8 as next digit of the result. 
Result so far: 1027942.8
If we take 168 away from 170, we end up with 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Moving on to step 10:
When dividing 20 by 21, we get 0 with a remainder of 20.
Put 0 as the next digit of the answer. 
Result so far: 1027942.8
Subtracting 0 from 20 leaves us with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Moving on to step 11:
21 can be fit into 200 9 times, resulting in a remainder of 11.
Write down 9 as next digit of the result. 
Result so far: 1027942.809
Deduct 189 from 200 and we're left with 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

On to step 12:
21 goes into 110 5 times with a remainder of 5.
Record the quotient 5 as the next digit in the result. 
Result so far: 1027942.8095
Subtracting 105 from 110 leaves us with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Step 13:
50 divided by 21 is 2 with a remainder of 8.
Write down 2 as next digit of the result. 
Result so far: 1027942.80952
If we subtract 42 from 50, we get 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Let's proceed to step 14:
When dividing 80 by 21, we get 3 with a remainder of 17.
Write down 3 as next digit of the result. 
Result so far: 1027942.809523
The remainder is 17 after subtracting 63 from 80.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Let's proceed to step 15:
170 divided by 21 is 8 with a remainder of 2.
The next digit of our result is 8. 
Result so far: 1027942.8095238
If we take 168 away from 170, we end up with 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Let's proceed to step 16:
If we divide 20 by 21, we get 0 and a remainder of 20.
The number 0 becomes the next digit in our result. 
Result so far: 1027942.8095238
Subtract 0 from 20 to get 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

The quotient of the division is 1027942.8095238, and the remainder is 2e-08.