1 followed by 30 zeroes would be a nonillion in US usage and a quintillion in Continental European and traditional British usage.
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Traditional British usage if by that you mean something that was abandoned around 50 year ago!
We call them by the number of their digits. Two-digit number, three-digit number and so on.
You would call it million.
There is no specific name: you just call it a number with 2 or more digits or a multi-digit number.
1,000,000,000,000 = one trillion
22 digits is verbally expressed with "Sextillion"
a Quadrillion is a 16 digit number
The largest 3 digit square number is 961 because 31*31 = 961
I would just call it a "400-digit number".
I suggest you just call it that - a "35-digit number".
We call them by the number of their digits. Two-digit number, three-digit number and so on.
31
You would call it million.
A doublelery
31
You are missing a digit. Find it.
sum
A rational number