My original suspicion was an issue with SAS mod function itself. It is actually because the number 11,169,568,236,203,649 is larger than the maxim integer9,007,199,254,740,992 supported by SAS PC vesion. It is a not a bug since it is clearly stated in the document that there is a maximum integer without rounding supported by SAS.
I was building random generators on both SAS and Oracle. It is required that given the same initial number, the random generators on SAS and Oracle will produce the same series of pseudo random numbers. Since it is impossible to match the SAS and Oracle results when the initial number is longer than 16 digits (Oracle integer supports 38 digits of precision), in my code I will throw an exception, stop the process and print a message similar to ORA-01438: "value larger than specified precision allowed for this column".