63561 ÷ 3 = 21187 R0
Alright, let's work through the division of 63561 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 (5) of the dividend behind the 0 and repeat the process: 5 / 3

Step 3:
3 goes into 5 1 times with a remainder of 2.
Write down 1 as next digit of of the result. 
Result so far: 211
Subtract 3 from 5 to get 2.
Bring next digit (6) of the dividend behind the 2 and repeat the process: 26 / 3

Step 4:
3 goes into 26 8 times with a remainder of 2.
Write down 8 as next digit of of the result. 
Result so far: 2118
Subtract 24 from 26 to get 2.
Bring next digit (1) of the dividend behind the 2 and repeat the process: 21 / 3

Step 5:
3 goes into 21 7 times with a remainder of 0.
Write down 7 as next digit of of the result. 
Result so far: 21187
Subtract 21 from 21 to get 0.

The final result is 21187 with a remainder of 0.