I pulled my TOTAL INVS PAID and my TOTAL DAYS TO PAY onto the grid view and discovered that the total invoices paid for the customers that were in the 65000, 32000 or 16000 days, were either 1 or 2 invoices.

Their respective Total Days to Pay were 65,535 or 16,766 or 32,767.
not sure where these values are coming from...