When you require to write the units of your x-axis values, you use the XLABEL function.
Now you can use XUNITS to add them right with the labels. And, if you like it, it could use International System Units prefixes instead of the scientific notation.

Besides, you get the same format for all the numbers (check the Screenshot).

It works for log scale as well as the linear one, and includes YUNITS and ZUNITS functions.

Finally, it works after zooming or panning.

Enjoy it!