@hackage number-length0.2.1.0

There are situations when it is necessary to know the length of a number in decimal or hexadecimal form. In example when allocating buffer while serializing a number in to binary or human readable format.

λ> numberLength (123 :: Int)
3

λ> numberLengthHex (123 :: Int)  -- 123 = 7b in hex
2