What is the biggest number in the Universe?

Here are the biggest named numbers in the world today.

By Toby Saunders

Published: Thursday, 15 June 2023 at 12:00 am

While it can be difficult to conceptualise a million of anything, it becomes harder still when that number rises to a billion, a trillion, quadrillion, quintillion or sextillion. But where is the final figure? Just what is the biggest number?

The idea that there’s a cap to the biggest a number can possibly be is one that’s stumped generations of mathematicians and scientists. Can there possibly be a number that’s so big we can’t squeeze any more digits on its end?

Keep on reading to discover everything you need to know about the world’s biggest number and why such a figure is likely impossible.

What is the world’s biggest number?

There is no biggest number, you cannot run out of numbers. We will never run out of numbers, even if going beyond a certain point removes any semblance of importance and real-world application.

There is no end in sight for numbers, but we will have to come up with new names for them. In quantum computing, for example, we can use ‘kilobytes’ all the way up to ‘yotta’ (10 to the power of 24). After this, there are not many agreed names, but more names may soon become a necessity.

So, what are the names of huge numbers that are agreed on? Everyone knows of the million, billion, and trillion, but what comes after that? Throughout the years, various scientists and mathematicians have pondered precisely this and have come up with a few ludicrously large numbers.

Avogadro’s number

As per the National Institute of Standards and Technology, “the Avogadro constant defines the number of particles in a mole, the SI unit that expresses the amount of substance. Simply put, Avogadro’s number of electrons equals one mole of electrons.”

Named after the first professor of physics in Italy, Amadeo Avogadro, the number written out reads 6.022 × 1023

Eddington number

The Eddington number represents the theorised total number of protons in the observable universe. As you’d expect, it’s a big one. This number is 136 × 2256, or about 1.57 × 1079.

Googol

One of the most well-known massive numbers, the Googol is the number one followed by one hundred zeros. This is represented as 10¹⁰⁰, but in full, the number is written:

10, ​000, ​000, ​000, ​000, ​000, ​000, ​000, ​000, ​000, ​000, ​000, ​000, ​000, ​000, ​000, ​000, ​000, ​000, ​000, ​000, ​000, ​000, ​000, ​000, ​000, ​000, ​000, ​000, ​000, ​000, ​000, ​000, ​000.

It was the inspiration for the name of the Google search engine given its many search results.

Googolplex

The Googolplex is 10googol or 1010^100. Essentially, it’s 10 to the power of googol.

Graham’s number

Finally, we have Graham’s number. It’s a figure invented by a mathematician called Ronald Graham in the 1970s to answer an obscure question in the field of Ramsey theory, which seeks to find order in the Universe’s chaos. The maths behind this number is incredibly complex, but the key thing to know is this number is large. Seriously large.

In fact, this number is so big that it’s actually bigger than the total number of atoms in the observable Universe – it’s bigger even than the googolplex!

The big problem with Graham’s number? It’s too big and hasn’t been written down in full before (there’s not enough space in the Universe for it!). It’s so large that it can’t be expressed like the googol, googolplex, Eddington number, or Avogrado’s number. However, we do know that its final 15 digits are 627262464195387.

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