APH has available an addendum to the Nemeth Code called “Ancient Numeration Systems”, adopted by BANA 1988. Rule V deals with Egyptian Signs and Symbols. I don’t know what your Egyptian numerals look like, but this might be the answer for you. Rule I of the Addendum explains the use and format of the symbols from Attic, Babylonian, Chinese-Japanese, Egyptian, Greek, Hebrew, and Mayan.
On the APH website (code books and instruction materials):
Addendum 1 to the Nemeth Code for Mathematics and Science Notation, 1972 Revision: Ancient Numeration Systems: Print Catalog Number: 7-68654-00 Format: Regular Print