63821 ÷ 3 = 21273 R2
Alright, let's work through the division of 63821 by 3 step by step.

Step 1:
3 goes into 6 2 times with a remainder of 0.
Write down 2 as next digit of of the result. 
Result so far: 2
Subtract 6 from 6 to get 0.
Bring next digit (3) of the dividend behind the 0 and repeat the process: 3 / 3

Step 2:
3 goes into 3 1 times with a remainder of 0.
Write down 1 as next digit of of the result. 
Result so far: 21
Subtract 3 from 3 to get 0.
Bring next digit (8) of the dividend behind the 0 and repeat the process: 8 / 3

Step 3:
3 goes into 8 2 times with a remainder of 2.
Write down 2 as next digit of of the result. 
Result so far: 212
Subtract 6 from 8 to get 2.
Bring next digit (2) of the dividend behind the 2 and repeat the process: 22 / 3

Step 4:
3 goes into 22 7 times with a remainder of 1.
Write down 7 as next digit of of the result. 
Result so far: 2127
Subtract 21 from 22 to get 1.
Bring next digit (1) of the dividend behind the 1 and repeat the process: 11 / 3

Step 5:
3 goes into 11 3 times with a remainder of 2.
Write down 3 as next digit of of the result. 
Result so far: 21273
Subtract 9 from 11 to get 2.

The final result is 21273 with a remainder of 2.