81421 ÷ 5 = 16284 R1
No problem, we've got 81421 and 5 for the division.

Step 1:
5 goes into 8 1 times with a remainder of 3.
Write down 1 as next digit of of the result. 
Result so far: 1
Subtract 5 from 8 to get 3.
Bring next digit (1) of the dividend behind the 3 and repeat the process: 31 / 5

Step 2:
5 goes into 31 6 times with a remainder of 1.
Write down 6 as next digit of of the result. 
Result so far: 16
Subtract 30 from 31 to get 1.
Bring next digit (4) of the dividend behind the 1 and repeat the process: 14 / 5

Step 3:
5 goes into 14 2 times with a remainder of 4.
Write down 2 as next digit of of the result. 
Result so far: 162
Subtract 10 from 14 to get 4.
Bring next digit (2) of the dividend behind the 4 and repeat the process: 42 / 5

Step 4:
5 goes into 42 8 times with a remainder of 2.
Write down 8 as next digit of of the result. 
Result so far: 1628
Subtract 40 from 42 to get 2.
Bring next digit (1) of the dividend behind the 2 and repeat the process: 21 / 5

Step 5:
5 goes into 21 4 times with a remainder of 1.
Write down 4 as next digit of of the result. 
Result so far: 16284
Subtract 20 from 21 to get 1.

The final result is 16284 with a remainder of 1.