Considering numbers in domain names - from SEO point of view

[Tim]

Hi Guys,

I'm curious.. Do numbers have any influence on keywords in domain names?
Are they considered as word separators (like the hyphens)? Or they are considered parts of the words?

For example.. If I register a domain name tires4cars.com - Would tires and cars be considered separate words here ?

[James]

I believe it's just counted as any other word in the domain name that's not seperated by a hyphen.