A couple are organising a large sporting event at which gold medals for winners each cost £36, silver medals for runners-up each cost £17 and bronze medals for third placed contestants each cost £11.

Normally there are a minority of events in which there are two semi-finals with each of the two losing contestants being given a bronze medal.  This year, however, the losing semi-finalists will compete for third place so that only one bronze medal will be awarded in all events.  This will reduce the number of medals needed by an odd number.

It was noticed that the total cost of all medals would now be a four digit palindrome.   This would also have been true had economies in the number of bronze medals not been made.

How many events are there?