There are no official information available regarding the number of candidates. Although from different resources, its alleged that around 60k-70k appears for the examination every year. The vacancies are not very much as a result the competition is quite hard. So if you wish to go for it then you must be very sure about your preparation.

To know more about IDBI executive examination visit the link below:

https://competition.careers360.com/exams/idbi-bank-executive

I hope this answer helps. All the very best for your future endeavors!