How can you tell if a Series 1934 Philadelphia $500 is fake? -

I have this $500 bill and is ripped off into halves. I don t know if its still usable but when I searched on the internet, it says that this denomination is not circulating anymore but can be sold to collectors. I searched some sites too to check if the dollar I have is real but Its really hard to tell. I don t have a U.S dollar bill with me and I can t compare it. I know how to identify Peso counterfieted bills but not dollar counterfieted bills. This is really hard. Please help.

not a travel question now, is it?