Listing total number of features into an ArcGIS Online feature pop-up

When configuring a feature service pop-up, how can I get the total number of features listed in the pop-up? For example, I have a hydrant service. When clicking on any hydrant, the pop-up would list the total amount of hydrants. Is there a way to do this with arcade, other than creating an integer field and adding "1" to every row and using the sum?