匹配“#”后跟数字“使用正则表达式php

I have this in a string. And need to get "USING REGULAR EXPRESSIONS" not explode not substr.. the words that follows "#123" or "#345345" the numbers vary in lenght.

String = "address number between #258 Kentucky";

In that case get Kentucky. I have used this but doesn't work.

\b#([0-9]+)\b

You cannot use \b (word boundary) before # which is a non-word character.

Just use this regex:

#([0-9]+)\s+(\w+)\b

RegEx Demo