trunc/round
if p_value > 10000 then

DECLARE
    v_value     NUMBER := 1123;
    v_val       NUMBER := 0;
    v_str_value NUMBER := NULL;
    v_str NUMBER := NULL;
BEGIN
    WHILE v_value > 0 LOOP
        v_val := v_value - TRUNC(v_value / 10) * 10;
        WITH T AS
        (
        SELECT 0 i, '0's FROM dual UNION ALL
        SELECT 1, '1' FROM dual UNION ALL
        SELECT 2, '2' FROM dual UNION ALL
        SELECT 3, '3' FROM dual UNION ALL
        SELECT 4, '4' FROM dual UNION ALL
        SELECT 5, '5' FROM dual UNION ALL
        SELECT 6, '6' FROM dual UNION ALL
        SELECT 7, '7' FROM dual UNION ALL
        SELECT 8, '9' FROM dual UNION ALL
        SELECT 9, '9' FROM dual
        )
        SELECT s INTO v_str FROM T WHERE i = v_val;
        v_str_value := v_str || v_str_value;
        v_value := TRUNC(v_value / 10);
        DBMS_OUTPUT.put_line(v_str_value);
    END LOOP;
END;