64371 ÷ 3 = 21457 R0
We're going to perform division on 64371 with 3 as the divisor.

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 (4) of the dividend behind the 0 and repeat the process: 4 / 3

Step 2:
3 goes into 4 1 times with a remainder of 1.
Write down 1 as next digit of of the result. 
Result so far: 21
Subtract 3 from 4 to get 1.
Bring next digit (3) of the dividend behind the 1 and repeat the process: 13 / 3

Step 3:
3 goes into 13 4 times with a remainder of 1.
Write down 4 as next digit of of the result. 
Result so far: 214
Subtract 12 from 13 to get 1.
Bring next digit (7) of the dividend behind the 1 and repeat the process: 17 / 3

Step 4:
3 goes into 17 5 times with a remainder of 2.
Write down 5 as next digit of of the result. 
Result so far: 2145
Subtract 15 from 17 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: 21457
Subtract 21 from 21 to get 0.

The final result is 21457 with a remainder of 0.