You can use the Mathematica "IntegerDigits[]" function to parse a student ID.  Assigning the function output to a variable saves (the list) by the variable name.

data  =  IntegerDigits[1141234]

data

Many Mathematica functions, when invoked on a list, simply perform that function on each element of the list in turn.

data  +  1

data ^ 2

Apply replaces the "List" head with the given function, in this case "Plus", which when evaluated adds the list's elements.

Apply[Plus,  data]

The number of elements in a list can be determined with the "Length[]" function.

Length[data]