If you have collate digits as numbers (CODAN) turned on, and you have >255
digits, the exponent silently wraps around.
Given the representation, there is no way to represent the number correctly.
Options for dealing with this are:
1. Silently wrap around (what it's doing now)
2. Silently peg at the maximum exponent
3. Abandon CODAN for this string and treat the number lexically
I would vote for number 2 or 3, though I think 3 is hard to implement (you're
pretty far down the garden path when you notice the problem). Once we decide I
can implement it.