A googol is a 1 with a hundred zeroes after it, denoted 10100, while a googolplex is 1 with a googol zeroes after it, denoted 10googol. The terms were coined by 9-year-old Milton Sirotta, nephew of American mathematician Edward Kasner, and were popularized in the book "Mathematics and the Imagination" (1940) by Kasner and James Newman.
A googol is a very large number. In fact, it is so large that it is hard to wrap one's head around it. To put it into perspective, the number of atoms in the observable universe is thought to be around 1078, which is dwarfed in comparison to a googol.
A googolplex is even larger than a googol, and is so large that it is hard to even conceive of. To put it into perspective, a googolplex is larger than the number of atoms in the observable universe by a factor of googol. In other words, a googolplex is unimaginably large. What is this number 10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000? This number is equal to 10 raised to the power of 200. In other words, it is equal to 1 followed by 200 zeroes. Is googolplex bigger than googol? Yes, a googolplex is bigger than a googol. In fact, a googolplex is infinitely bigger than a googol. How many zeros are behind a googolplex? There are an infinite number of zeros behind a googolplex. Is googolplex bigger than infinity? Mathematically speaking, infinity is not a number, but rather an idea of something without an end. That being said, googolplex is a number (10^(10^100)), and as such is finite. Therefore, googolplex is not bigger than infinity.
What comes after a zillion?
A zillion is a very large number. The exact definition of a zillion varies depending on the particular numbering system. In the English language, a zillion is typically a large indefinite number. In the short scale system, a zillion is a number with at least three zeroes after the first digit (1000 or greater). In the long scale system, a zillion is a number with at least six zeroes after the first digit (1,000,000 or greater).