The highest number known to man is infinity. Infinity is not a number in the traditional sense, but rather it is an idea of something without an end. It is often used in mathematics to represent things that go on forever or are too large to be measured. The concept of infinity has been around for centuries and has been studied by some of the greatest minds in history. Infinity is not just a number, but rather it represents a whole new way of thinking about the world and the universe.