is there any way I can check on my thread how many people subscribed and getting its notification?
Why do you want such data? If the primary goal is to know how much they interact with you, it is best to measure your views and responses.
I don’t know how the views work, but I think it’s related to the number of times registered accounts view your topic.
Also, I don't think many know @notify benefit, so knowing who to press on it, mean nothing.
It does not matter how many click @notify, but their interaction with you.