17 x 2^16 = 17 x 2^13 x 2^3
(reposted/edited because * was interpreted as formatting)
Right, I guess I was thinking more of "not a power of 2" instead of "not a multiple of 8".
On second thought, the author might have meant "Sorry that the exponent is not a multiple of 8" as in Unicode neither has 2^16 nor 2^32 code points.
17 x 2^16 = 17 x 2^13 x 2^3
(reposted/edited because * was interpreted as formatting)