Happy Numbers in COBOL

As the title implies, I'm doing a software that calculate and verify if the number inserted is a happy number (OR NOT). In COBOL language (For reference about what a happy number is https://mathworld.wolfram.com/HappyNumber.html).

Right now, my code doesnt calculate correctly if the number is happy or not (In the program HEY = Happy and HOY = not happy :C)

My question is, what am i doing wrong in the code? All i need now is to properly detect if its happy or not. Any help is well welcome.

This is my current code:

IDENTIFICATION DIVISION.
       PROGRAM-ID. YOUR-PROGRAM-NAME.
       DATA DIVISION.
       FILE SECTION.
       WORKING-STORAGE SECTION.
       01 num PIC 9(36).
       01 addc PIC 9(36).
       01 rem PIC 9(36).
       01 pow PIC 9(36).
       01 toast PIC 9.
       01 k PIC 999 VALUE 0.
       01 l PIC 9(36).
       PROCEDURE DIVISION.
       MAIN-PROCEDURE.
           DISPLAY"Escribe numero "
           ACCEPT num
           PERFORM WITH TEST AFTER UNTIL addc = 1
               MOVE 0 TO addc
               PERFORM WITH TEST AFTER UNTIL num = 0
                   DIVIDE num BY 10 GIVING num REMAINDER rem
                   MULTIPLY rem BY rem GIVING pow
                   MOVE pow TO addc
               END-PERFORM

               IF addc = 1
                   MOVE 1 TO toast
               ELSE
                   MOVE addc TO num
                   ADD 1 TO k
                   IF k = 20
                       MOVE 1 TO addc
                       MOVE 0 TO toast
                   END-IF
               END-IF
           END-PERFORM

           IF toast = 1
               DISPLAY "HEY"
           ELSE
               DISPLAY "HOY"
           END-IF
            STOP RUN.
       END PROGRAM YOUR-PROGRAM-NAME.

Also, as an extra question, how can i handle numbers above the maximum limit of 36? without using the equivalent of strings and chars in Cobol.