20491 ÷ 4 = 5122 R3
Let's divide 20491 by 4.

Step 1:
4 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 (0) of the dividend behind the 2 and repeat the process: 20 / 4

Step 2:
4 goes into 20 5 times with a remainder of 0.
Write down 5 as next digit of of the result. 
Result so far: 5
Subtract 20 from 20 to get 0.
Bring next digit (4) of the dividend behind the 0 and repeat the process: 4 / 4

Step 3:
4 goes into 4 1 times with a remainder of 0.
Write down 1 as next digit of of the result. 
Result so far: 51
Subtract 4 from 4 to get 0.
Bring next digit (9) of the dividend behind the 0 and repeat the process: 9 / 4

Step 4:
4 goes into 9 2 times with a remainder of 1.
Write down 2 as next digit of of the result. 
Result so far: 512
Subtract 8 from 9 to get 1.
Bring next digit (1) of the dividend behind the 1 and repeat the process: 11 / 4

Step 5:
4 goes into 11 2 times with a remainder of 3.
Write down 2 as next digit of of the result. 
Result so far: 5122
Subtract 8 from 11 to get 3.

The final result is 5122 with a remainder of 3.