How to pass function with argument in addEventListener ?

Question

I want to execute a function with argument from addEventListener on button click. i wrote some code,but here function is executing before button click.....below sample code....

<form>
   <button id="btn">Click Here</button>
       </form>
   <script>

       function abc(num) {
           alert(num);
       };

       document.getElementById('btn').addEventListener('click', abc(2));
   </script>

help me how to solve this problem...