25805

It could be either 320 or 136. The T could mean triangular meaning that the 16th triangular number-136. Or, T is the 20th letter in the alphabet so if you times it by 16, it equals 320. However, if this could be a harder version, the criminals/spies could code name the T meaning say 50. Fortunately, this is a stage 2 challenge, therefore the code cannot be that difficult as it would be impossible to crack it without the case. There would be 1000 different combinations to try! However, that is far from the 4 digit 10000!