Necessity of writing the number “404” on a 404 page?

I’ve been working on a 404 page recently and have been confronted with the issue of whether we need to explicitly write the numbers ‘404’ on the 404 page.

My team’s opinion on this issue is split. I don’t think that the average user knows or cares what 404 means (our average user is fairly non-technical).

Does anyone know of any studies or have a strong opinion about this?