Mathwords logoMathwords

Googolplex

Googolplex

The number 10googol, or 1 followed by a googol number of zeros. This is reputed to be the largest number with a name.

Note: This can also be written 10(10^100).

Key Formula

googolplex=1010100\text{googolplex} = 10^{10^{100}}
Where:
  • 1010010^{100} = A googol, which is the exponent applied to the base 10

Example

Problem: Express a googolplex using repeated exponentiation, and compare its size to a googol.
Step 1: Start with a googol, which is 1 followed by 100 zeros.
googol=10100\text{googol} = 10^{100}
Step 2: A googolplex uses that entire googol as the exponent on 10.
googolplex=10googol=1010100\text{googolplex} = 10^{\text{googol}} = 10^{10^{100}}
Step 3: If you tried to write a googolplex out in full decimal form, you would write the digit 1 followed by 1010010^{100} zeros. A googol itself only has 100 zeros, so a googolplex has incomprehensibly more digits.
Answer: A googolplex is 101010010^{10^{100}}. Writing it out would require a googol digits — far more zeros than there are atoms in the observable universe (roughly 108010^{80}).

Why It Matters

A googolplex illustrates how quickly repeated exponentiation (also called tetration) produces numbers beyond any physical meaning. The observable universe does not contain enough particles to write out a googolplex digit by digit, making it a useful benchmark when discussing the limits of computation and the scale of large numbers.

Common Mistakes

Mistake: Confusing a googolplex (101010010^{10^{100}}) with a googol (1010010^{100}).
Correction: A googol is 1 followed by 100 zeros. A googolplex is 1 followed by a googol zeros — an astronomically larger number. The googol serves as the exponent in a googolplex.

Related Terms

  • GoogolThe exponent used to define a googolplex
  • ZeroA googolplex is 1 followed by a googol zeros
  • ExponentGoogolplex is defined via repeated exponentiation
  • PowerA googolplex is a power of 10