21543 ÷ 7 = 3077 R4
Alright, let's work through the division of 21543 by 7 step by step.

Step 1:
7 goes into 2 0 times with a remainder of 2.
Write down 0 as next digit of of the result. 
Result so far: 0
Subtract 0 from 2 to get 2.
Bring next digit (1) of the dividend behind the 2 and repeat the process: 21 / 7

Step 2:
7 goes into 21 3 times with a remainder of 0.
Write down 3 as next digit of of the result. 
Result so far: 3
Subtract 21 from 21 to get 0.
Bring next digit (5) of the dividend behind the 0 and repeat the process: 5 / 7

Step 3:
7 goes into 5 0 times with a remainder of 5.
Write down 0 as next digit of of the result. 
Result so far: 30
Subtract 0 from 5 to get 5.
Bring next digit (4) of the dividend behind the 5 and repeat the process: 54 / 7

Step 4:
7 goes into 54 7 times with a remainder of 5.
Write down 7 as next digit of of the result. 
Result so far: 307
Subtract 49 from 54 to get 5.
Bring next digit (3) of the dividend behind the 5 and repeat the process: 53 / 7

Step 5:
7 goes into 53 7 times with a remainder of 4.
Write down 7 as next digit of of the result. 
Result so far: 3077
Subtract 49 from 53 to get 4.

The final result is 3077 with a remainder of 4.