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Ṁ_Ṃ
sLÆD$ḌÇÞṪL


A monadic link taking a list of integers (the digits) and returning an integer.

Try it online! or see a test-suite

How?

Ṁ_Ṃ - Link 1, maximal difference: list of numbers
Ṁ   - maximum
  Ṃ - minimum
 _  - subtract

sLÆD$ḌÇÞṪL - Main link: list of numbers, theDigits  e.g. [1,2,3,0,0,1]
    $      - last two links as a monad:
 L         -   length                                    6
  ÆD       -   divisors                                  [1,2,3,6]
s          - split into chunks (vectorises)              [[[1],[2],[3],[0],[0],[1]],[[1,2],[3,0],[0,1]],[[1,2,3],[0,0,1]],[[1,2,3,0,0,1]]]
     Ḍ     - from decimal (vectorises)                   [[1,2,3,0,0,1],[12,30,1],[123,1],[123001]]
       Þ   - sort by:
      Ç    -   call last link (1) as a monad              3             29        122     0
           -                                         ... [[123001],[1,2,3,0,0,1],[12,30,1],[123,1]]
        Ṫ  - tail                                        [123,1]
         L - length                                      2