2.. 148877. Remove the last three digits of 877 to get 148000.
Because the cube of 5 is 125, then the cube of 50 is 125000 (less than 148000).
Similarly, the cube of 6 is 2 16, so the cube of 60 is 2 16000 (greater than 148000).
So 148877 is the cube of the 1950s.
Look again,
148877 bit is 7. Let's guess, which number is cubic 7? There are only three, so it is 53.