Test if given number is a Reverse Keith?
APL (28)

⍙∊{1↓⍵,+/⍵}⍣{⊃⍺≥⍙∘←⍎⌽∆}⍎¨∆←⍞


Using more or less the same method as TwiNight did in the other question but reversing the number.

Explanation:


∆←⍞: read a line as text, store in ∆
⍎¨: evaluate each character
{1↓⍵,+/⍵}: add the sum of the list to the end of the list, and drop the first item,
⍣: until
{⊃⍺≥⍙∘←⍎⌽∆}: the first item on the list is greater or equal to ⍙, which is the evaluation (⍎) of the reverse (⌽) of ∆.
⍙∊: see if ⍙ is contained in the final list.