A four digit positive decimal number DEEP ( in which each of the letters D, E and P represent a different digit) is expressed in base 7, base 6 and base 5. Treating these expressions as decimal numbers, we add them together and observe that the total is 20000. What does DEEP represent?

Another four digit positive decimal number ROOT ( in which each of the letters R, O and T represent a different digit) is expressed in base 7, base 6 and base 5. Treating these expressions as decimal numbers, we add them together and observe that the total is 54321. What does ROOT represent?