I have a dataset of 130k internet users characterized by 4 variables describing users' number of sessions, locations visited, avg data download and session time aggregated from four months of activity.

Dataset is very heavy-tailed. For example third of users logged only once during four months, whereas six users had more than 1000 sessions.

I wanted to come up with a simple classification of users, preferably with indication of the most appropriate number of clusters.

Is there anything you could recommend as a solution?