User blog comment:Ikosarakt1/Apocalyptic function/@comment-5529393-20130321020848/@comment-5150073-20130322120741

Yes, I also found that 2^29784 is the largest power of two <= 2^100000 that is non-apocalyptic. By the way, I haven't built-in arbitrary precision arithmetic (my program language is Pascal), so I had to do some tricks to get the large powers of two.