You do realize your mathematical problem here, yes?

Start with one universe and 1 portal. It gets turned on, two universes, both with portals.

You turn on your portal again. Four universes, all with portals. One of them activates. Eight universes. Two of them are turned on one right after the other. Thirty-two universes. Three of them turn on portals. Now 256 universes, all with portals. Ten portals get turned on the next day: 662,144 universes. The next day is a quiet one; only 50 of those universes turn on their portals.

You're now at 2.9514 x 10<sup>20</sup> universes. How many of them decide to turn on their portals?

It doesn't matter what kind of numbering or naming system you chose; you'll very quickly realize you've run out of any kind of practical method.

**ADDENDUM**

Additional problem: how can you know what name your universe is? If opening a portal causes all the universes as they currently exist to duplicate exactly, then how do the "new" universes know they're new, especially if they're created as a result of someone else triggering a portal in a universe no longer connected to yours?