Find the number of all whole numbers formed on the screen of a calculator which can be recognised as numbers with (unique) correct digits when they are read inverted. The greatest number formed onn its screen is 999999.

Explanation

The number can use digits 0,1,2,5,6,8 and 9 because they can be recognised as digits whey they are see inverted.
A number can't beginn with, therefore all numbers having at unit's digit should no be counted. (when those numbers will be read inverted they will begin with).