floating point - float division in unityscript -

Why does this code as 536870 9 12 as output and 536870911.5?

  var z: double = 1073741823.0 / 2.0; Debug.Log (z.ToString ("F15"));   
 And how can I get this 536870911.5 output? It seems strange to me ...   
 
 
 You can use it by using C #:  
  double test = 1073741823.0d / 2.0d; // = 536870911.5 debug Log (test);   
 
 And in the Unity script, you only need to add DS  
  var test: double = 1073741823.0d / 2.0d; // = 536870911.5 debug Log (test);   
 
 Without double notation, the Unity script is parsing the number as another type. (Most likely an integer)  
 does not work as the interpreter is not casting them properly:  
  var test: double = 1073741823.0 / 2.0; // = 536870912 debug Log (test);   
 I think it is reading:  double = int / int;   
 
 Very interesting This is another reason I encourage developers to go to C #.