21210164 ÷ 812 
We want to figure out the number of times 21210164 can be divided by 812.

Let's proceed to step 1:
When dividing 2 by 812, we get 0 with a remainder of 2.
The next digit of our result is 0. 
Result so far: 0.0
Subtracting 0 from 2 leaves us with 2.
Include the next digit (1) from the dividend after 2, then repeat: 21 / 812

Going ahead to step 2:
812 goes into 21 0 times with a remainder of 21.
Use 0 as the next digit of our solution. 
Result so far: 0.0
The remainder is 21 after subtracting 0 from 21.
Grab the next digit (2) from the dividend, add it to 21, then carry on: 212 / 812

Advancing to step 3:
When dividing 212 by 812, we get 0 with a remainder of 212.
The next digit of our result is 0. 
Result so far: 0.0
If we subtract 0 from 212, we get 212.
Grab the next digit (1) from the dividend, add it to 212, then carry on: 2121 / 812

Advancing to step 4:
If we divide 2121 by 812, we get 2 and a remainder of 497.
The number 2 becomes the next digit in our result. 
Result so far: 2.0
Deduct 1624 from 2121 and we're left with 497.
Bring next digit (0) of the dividend behind the 497 and repeat the process: 4970 / 812

On to step 5:
When dividing 4970 by 812, we get 6 with a remainder of 98.
The next digit of our result is 6. 
Result so far: 26.0
The remainder is 98 after subtracting 4872 from 4970.
Include the next digit (1) from the dividend after 98, then repeat: 981 / 812

Moving on to step 6:
981 divided by 812 is 1 with a remainder of 169.
Record the quotient 1 as the next digit in the result. 
Result so far: 261.0
The remainder is 169 after subtracting 812 from 981.
Include the next digit (6) from the dividend after 169, then repeat: 1696 / 812

Going ahead to step 7:
1696 divided by 812 is 2 with a remainder of 72.
Put 2 as the next digit of the answer. 
Result so far: 2612.0
If we subtract 1624 from 1696, we get 72.
Include the next digit (4) from the dividend after 72, then repeat: 724 / 812

Step 8:
724 divided by 812 is 0 with a remainder of 724.
Record the quotient 0 as the next digit in the result. 
Result so far: 26120.0
If we subtract 0 from 724, we get 724.
Since there are no more digits in the dividend, we add a zero to the remainder making it 7240, and continue the process.

Step 9:
When dividing 7240 by 812, we get 8 with a remainder of 744.
Put 8 as the next digit of the answer. 
Result so far: 26120.8
Deduct 6496 from 7240 and we're left with 744.
Since there are no more digits in the dividend, we add a zero to the remainder making it 7440, and continue the process.

Moving on to step 10:
7440 divided by 812 is 9 with a remainder of 132.
The next digit of our result is 9. 
Result so far: 26120.89
Subtract 7308 from 7440 to get 132.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1320, and continue the process.

Let's proceed to step 11:
If we divide 1320 by 812, we get 1 and a remainder of 508.
The number 1 becomes the next digit in our result. 
Result so far: 26120.891
If we take 812 away from 1320, we end up with 508.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5080, and continue the process.

Advancing to step 12:
When dividing 5080 by 812, we get 6 with a remainder of 208.
Record the quotient 6 as the next digit in the result. 
Result so far: 26120.8916
If we subtract 4872 from 5080, we get 208.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2080, and continue the process.

On to step 13:
The number 812 fits into 2080 2 times, leaving a remainder of 456.
Write down 2 as next digit of the result. 
Result so far: 26120.89162
If we subtract 1624 from 2080, we get 456.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4560, and continue the process.

Moving on to step 14:
812 can be fit into 4560 5 times, resulting in a remainder of 500.
Record the quotient 5 as the next digit in the result. 
Result so far: 26120.891625
Subtract 4060 from 4560 to get 500.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5000, and continue the process.

Moving on to step 15:
812 can be fit into 5000 6 times, resulting in a remainder of 128.
Record the quotient 6 as the next digit in the result. 
Result so far: 26120.8916256
Deduct 4872 from 5000 and we're left with 128.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1280, and continue the process.

Step 16:
If we divide 1280 by 812, we get 1 and a remainder of 468.
The next digit of our result is 1. 
Result so far: 26120.89162561
If we take 812 away from 1280, we end up with 468.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4680, and continue the process.

In conclusion, the division gives 26120.89162561 with a balance of 4.68e-07.