What is the base for the Egyptian number system?

Answer 1

You are making a mistake. To talk of a base only makes sense in talking of a positional numbering system as this
4320 means 4 1000's, 3 100's, 2 ten's and no 1's in the base 10 system while it means other things in other bases and with multiplication.
But Egyptian numbers had no zero and were not positional and multiplication was done by repeated adding, they had symbols for each exponent of 10 http://www.psinvention.com/zoetic/tr_egypt.htm and probably, at certain times in their several thousand years, had symbols for 5 (like the Roman V), 12 (like dozen), 25, 50 (Roman L) and 60 (used in navigation, like minutes in hour)
To write a number like the one above one had to write 4 symbols for 1000, 3 symbols for 100, and two for 10 (9 symbols) and since they had the same value in any order, they could be written rows, in groups or in columns.