If one sets A=1, B=2, ... Z=26, it is well-known that no number-name is self expressive (15+14+5 does not add to ONE, 20+23+15 to TWO, etc.). However, there are other ways to arithmetically combine numbers.
Eckler, A. Ross
"Self-Expressive Number Names,"
Word Ways: Vol. 40
, Article 8.
Available at: http://digitalcommons.butler.edu/wordways/vol40/iss4/8