Hello,
A number like 2e+007 is in scientific notation, and is a short-hand way to write 20,000,000.
You cannot change the notation in the graph, but you can always export the data in a graph to a comma-separated text file (CSV) or directly to Excel if you are using a Windows computer. That makes it possible to use a spreadsheet program to graph the data with as much control as you like.
To export data from a graph, just right-click it (control-click on a Mac), and choose an option from the shortcut menu.
Best regards,
Paul.