That's very unusual. For numbers between a thousand and two thousand, we can say 'eleven hundred' (1100) 'twelve hundred' (1200) and so on, but it's not normal to say 'twenty hundred'.

No., it's not used in any situation. For an multiple of 10 you never use hundreds, only thousands. For numbers in between you can use hundreds or thousands and hundreds Two thousand Twenty-one hundred or two thousand one hundred Twenty-two hundred or two thousand two hundred .... Three thousand And so on up to ninety nine hundred. After 10,000 you can't use the hundreds method.

I've NEVER heard "twenty hundred" used as an ordinary number, never. Nineteen hundred, yes, twenty-one hundred yes, twenty-hundred no. The only place I might have heard it, and I'm not even sure about that, is with reference to time on the 24-hour system. It seems me the 20:00 might be read as "twenty hundred hours." Certainly 19:00 is "nineteen hundred hours" and 02:00 is "oh two hundred hours." Pretty weird and totally illogical in terms of arithmetic.

It is common enough to say things like "twenty hundred". It would be more normal to say "two thousand" but it is possible to say it differently depending on your preference. The rules are not as rigid as they are in Spanish regarding numbers. This is especially true when stating numbers like those in an address. For instance, it would be perfectly normal for someone to say the address "6425 Main St." as "sixty four twenty five Main street".