Can 余 (more than) go after the measure word?

Question

I've just learned a new formal word 余 and I'm trying to understand it's placement. I know that roughly it means 多 but in a more formal way. If for example, I was saying "more than 500 people" I think I could say both

五百多人， and 五百人多 （correct me if I'm wrong on this one)

However, could I say

五百余人？ 五百人余？

Answer 1

• 五百多人 is correct and colloquial.
• 五百余人 is correct and formal.
• 五百人多 is not correct.
• 五百人余 is not grammatical in modern Mandarin but contextually valid in ancient Chinese. It may appear a lot in ancient stories written in vernacular language.