The count appears to be random.

Before I went away for a few days, the count was above 2,000. (I rarely look at them.)

When I returned, the count was 36.

Next day it was 47.

Now it is 23

Is there any logic in the count?

Or maybe it is for generating lottery numbers?

(My recollection of the count may not be 100% accurate, but I think that you should get the gist.)

The method to "clear notifications" is no longer available, many complained about the extensive pages of notifications they had , so we were able to adjust that to a much shorter period, thereby reducing dramatically the list of notifications. That would explain your substantial drop in numbers.