A googol is the lairge nummer 10¹⁰⁰; that is, the digit 1 follaed bi 100 zeroes:

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.

The term wis coined in 1938^[1] bi 9-year-auld Milton Sirotta, nephew o American mathematician Edward Kasner. Kasner popularized the concept in his 1940 beuk Mathematics and the Imagination.

Ither names for googol include ten duotrigintillion on the short scale, ten thoosand sexdecillion on the long scale, or ten sexdecilliard on the Peletier lang scale.

A googol haes na particular signeeficance in mathematics, but is uiseful when comparin wi ither very lairge quantities such as the nummer o subatomic pairticles in the veesible universe or the nummer o hypothetically possible chess genmes. Edward Kasner uised it tae illustrate the difference atween an unimaginably lairge nummer an infinity, an in this role it is sometimes uised in teachin mathematics.

A googol is approximately 70! (factorial o 70). In the binary numeral seestem, ane would need 333 bits tae represent a googol, i.e., 1 googol ≈ 2^332.2, or exactly ${\displaystyle 2^{(100/\mathrm {log} _{10}2)}}$.

Googol is notable for bein the subject o the £1 million question in the infamous episode o Who Wants to Be a Millionaire?, when contestant Charles Ingram cheatit his way through the shaw bi gettin help frae his wife, who wis in the audience, an fellae contestant Tecwen Whittock. It is an aa the namesake o the internet company Google, wi the name "Google" bein a misspellin o "googol" bi the company's founders.^[2]

Tae gie a sense o hou big a googol really is, the mass o an electron, juist unner 1×10^-30 kg, can be compared tae the mass o the entire universe, estimatit at atween 1×10⁵⁰kg an 1×10⁶⁰ kg.^[3] It is a ratio in the order o aboot 10⁸⁰ tae 10⁹⁰, still much smawer than the value o a googol.