googolplex

Googolplex is an extremely large finite integer defined as 10 raised to the power of a googol, i.e., 10^(10^100). A googol itself is 10^100, so a googolplex is 1 followed by a googol zeros. In decimal notation this is a 1 with an unimaginably large number of zeros.

The term was introduced in the 1930s as part of a pair of concepts popularized by American mathematician Edward Kasner and his nine-year-old nephew Milton Sirotta. Milton is credited with coining the word googol; Kasner and his colleague James Newman helped promote the ideas in their 1940 book Mathematics and the Imagination. The googolplex was defined by Kasner as the next-step extension, 10^(googol), to illustrate the scale of very large numbers.

In practical terms, a googolplex is so large that it cannot be written out in full in standard decimal notation. The number of digits would be googol + 1, or about 10^100 digits, far exceeding the estimated number of particles in the observable universe (around 10^80). This makes any physical representation of a googolplex infeasible.

Beyond its size, the googolplex is mainly used as an educational example to contrast finite but astronomically large quantities with infinity. The name also inspired the company name Google, a deliberate nod to the mathematical term googol.