There is no specific name: you just call it a number with 2 or more digits or a multi-digit number.
a Quadrillion is a 16 digit number
No. When adding the smallest 2 digit number (= 10) to the smallest 2 digit number (again, 10) the result is a 2 digit number (10 + 10 = 20). When adding the largest 2 digit number (= 99) to the largest 2 digit number (again, 99) the result is a 3 digit number (99 + 99 = 198). As you can see, you'll either get a 2 or 3 digit number, but never a 4 digit number.
2
2 digit number
I suggest you just call it that - a "35-digit number".
I would just call it a "400-digit number".
We call them by the number of their digits. Two-digit number, three-digit number and so on.
0
product means multiplication. so a 2 digit number multiplied by a 4 digit number. 80 x 6250 = 500,000 80 can be your 2 digit number 6250 can be your 4 digit number
10 is the smallest 2 digit number.
You would call it million.