Edward Kasner, a prominent American mathematician, had a 9 year old nephew. In 1938 the nephew came up with the term “googol”, which was 10100. Later the kid came up with the idea of “googolplex”, which was the number 1 followed by countless zeros. Their number wasn’t really accurate, as according to the kid it would continue until the person writing got tired of writing zeros.
Nowadays the number googolplex indicates 1010100. There are several ways in pure mathematics for representing the magnitude of googolplex, including tetration, Knuth’s up-arrow notation, Steinhaus – Moser notation and Conway chained arrow notation.
In reality it’s impossible to write down a googolplex. It’s estimated that even if all the following zeros were to be written on every single particle of the known parts of the universe, it would require more space. Not only space, but also time would be a factor if somebody decided to write down all of those zeros. It would take 1.1×1082 times the age of the universe in order to write such a number.