Divine number and letter mentioned? (7)
I believe the answer is:
foresee
'divine' is the definition.
(I've seen this in another clue)
'number and letter mentioned?' is the wordplay.
'number' becomes 'fore' (I am not sure about this - if you are sure you should believe this answer much more).
'and' is a charade indicator (letters next to each other).
'letter' becomes 'c'.
'mentioned?' indicates a 'sounds like' (homophone) clue (I've seen 'mentioned' mean this).
'c' is a homophone of 'see'.
'fore'+'see'='FORESEE'
(Other definitions for foresee that I've seen before include "To know beforehand" , "Imagine" , "witness in advance?" , "Realise or be aware of in advance" , "Envisage" .)