Generate random number in delphi

i want to create a random number in delphi and assign it to file as a file name. I managed to do that but when i click button to generate number it always start with a 0. Any idea how to fix it

procedure TForm1.Button1Click(Sender: TObject);
var
test:integer;

begin
test:= random(8686868686868);

edit1.Text:= inttostr(test);
end;

end.