Amitabh Bachchan has proved that age is just a number and it does not have to do anything with work. The actor, who turned 79 on October 11, has many films lined up in his kitty. At this age, he is one of the busiest actors in Bollywood and is also hosting the game reality show Kaun Banega Crorepati 13. Actors from his era have retired from work, but Amitabh Bachchan is still going strong. However, recently veteran writer Salim Khan said that the actor should retire now.