The number five crore twenty three lakh seventy eight thousand four hundred one can be written, using commas, in the Indian System of Numeration as _____.

By reversing the order of digits of the greatest number made by five different non - zero digits, the new number is the _____ number of five digits.

By adding 1 to the greatest_____ digit number, we get ten lakh.

In Roman Numeration, the symbol X can be subtracted from_____, M and C only.

The number 66 in Roman numerals is_____.