The most common and most likely answer to this crossword clue is the 6 letter word GOOGOL
I've seen this crossword clue in Independent
G
O
O
G
O
L
More clues leading to the result GOOGOL
- Huge figure of Russian writer seizing doughnut
- A large number try returning small design
- Huge figure has to travel into Yorkshire town, shortly
- Huge number shot in East Yorks town after docking
- Number search engine reported, roughly speaking
- Pass mark upset a very large number
- Try uplifting sign given by an enormous number
- O2 deleting digit in writer’s long number
Buddy explains!

The straight part
We know that "A large number" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case a large number = googol.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does GOOGOL mean?
GOOGOL numeral- The number 10^{100}, or ten to the power of a hundred.