How many zeros in 999 googol?

There are One Hundred Zeroes in a Googol.

So the answer to your question is 999 followed by one hundred zeroes or 999*10100 or even 9,990,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,

000,000,000,000,000,000,000,000,000,000,000,000,000,000,000

A rather large number.