21397412 divided by 390 
The aim is to understand the frequency of 390 in 21397412.

Advancing to step 1:
390 can be fit into 2 0 times, resulting in a remainder of 2.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 2 after subtracting 0 from 2.
Grab the next digit (1) from the dividend, add it to 2, then carry on: 21 / 390

Step 2:
390 can be fit into 21 0 times, resulting in a remainder of 21.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 21 to get 21.
Grab the next digit (3) from the dividend, add it to 21, then carry on: 213 / 390

Advancing to step 3:
If we divide 213 by 390, we get 0 and a remainder of 213.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we take 0 away from 213, we end up with 213.
Take the next digit (9) from the dividend and append it to 213, then repeat: 2139 / 390

Let's proceed to step 4:
When dividing 2139 by 390, we get 5 with a remainder of 189.
The next digit of our result is 5. 
Result so far: 5.0
If we take 1950 away from 2139, we end up with 189.
Include the next digit (7) from the dividend after 189, then repeat: 1897 / 390

Advancing to step 5:
The number 390 fits into 1897 4 times, leaving a remainder of 337.
The number 4 becomes the next digit in our result. 
Result so far: 54.0
If we take 1560 away from 1897, we end up with 337.
Grab the next digit (4) from the dividend, add it to 337, then carry on: 3374 / 390

Advancing to step 6:
390 goes into 3374 8 times with a remainder of 254.
Write down 8 as next digit of the result. 
Result so far: 548.0
If we take 3120 away from 3374, we end up with 254.
Include the next digit (1) from the dividend after 254, then repeat: 2541 / 390

Step 7:
2541 divided by 390 is 6 with a remainder of 201.
The next digit of our result is 6. 
Result so far: 5486.0
Deduct 2340 from 2541 and we're left with 201.
Include the next digit (2) from the dividend after 201, then repeat: 2012 / 390

Moving on to step 8:
When dividing 2012 by 390, we get 5 with a remainder of 62.
Put 5 as the next digit of the answer. 
Result so far: 54865.0
Subtracting 1950 from 2012 leaves us with 62.
Since there are no more digits in the dividend, we add a zero to the remainder making it 620, and continue the process.

Step 9:
390 can be fit into 620 1 times, resulting in a remainder of 230.
Write down 1 as next digit of the result. 
Result so far: 54865.1
Deduct 390 from 620 and we're left with 230.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2300, and continue the process.

Let's proceed to step 10:
390 can be fit into 2300 5 times, resulting in a remainder of 350.
Put 5 as the next digit of the answer. 
Result so far: 54865.15
Subtracting 1950 from 2300 leaves us with 350.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3500, and continue the process.

Going ahead to step 11:
When dividing 3500 by 390, we get 8 with a remainder of 380.
Put 8 as the next digit of the answer. 
Result so far: 54865.158
Subtracting 3120 from 3500 leaves us with 380.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3800, and continue the process.

Advancing to step 12:
3800 divided by 390 is 9 with a remainder of 290.
The next digit of our result is 9. 
Result so far: 54865.1589
If we subtract 3510 from 3800, we get 290.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2900, and continue the process.

On to step 13:
390 goes into 2900 7 times with a remainder of 170.
Record the quotient 7 as the next digit in the result. 
Result so far: 54865.15897
Deduct 2730 from 2900 and we're left with 170.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1700, and continue the process.

Moving on to step 14:
390 can be fit into 1700 4 times, resulting in a remainder of 140.
The next digit of our result is 4. 
Result so far: 54865.158974
If we take 1560 away from 1700, we end up with 140.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1400, and continue the process.

Going ahead to step 15:
390 goes into 1400 3 times with a remainder of 230.
The next digit of our result is 3. 
Result so far: 54865.1589743
If we take 1170 away from 1400, we end up with 230.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2300, and continue the process.

Advancing to step 16:
390 goes into 2300 5 times with a remainder of 350.
The next digit of our result is 5. 
Result so far: 54865.15897435
Deduct 1950 from 2300 and we're left with 350.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3500, and continue the process.

In conclusion, the division gives 54865.15897435 with a balance of 3.5e-07.