How to use wildcard in email search (?)

How to use wildcard in email search (?)

I'm trying to find an email with an account number, of which I only know the last four digits (5163). When I search for 5163, I get several results from sender A who wrote my account number as ********5163 in the body. When I search for 163, I get several results from sender B who wrote my account number as ********163, but NOTHING from sender A.

Obviously, if I knew the entire string, I wouldn't bother searching for it. How do I throw a wildcard into my search so I can find my full account number via partial match? This is unbelievably/pointlessly frustrating!