If I just switched to Production mode and have zero accounts, why is Analytics showing XX numbers?

If you previously had test accounts under your sandbox account, just cleared your test data and then switched to Production mode, then the old test data will still appear in the Analytics dashboard until the updates the following day. Keep in mind that the Analytics dashboard currently updates every 24 hours, so the cleared data will not update until the following day. For now, the Analytics data will still reflect the old test data before it was cleared.