84599 is a decent NNNNN.com, 123k google results, not a zip code apparently, but as is typical with numerics the domain is the second thing that came up when I type in the number into google search, so that's good. Estibot says $50. Apparently people also search for wpd800 (mountain bike?) along with the number. Also, check archive.org, it used to be a developed site, which is nice.
40628 has 501,000 google results, Estibot says $60 for this, which is more than what the market will pay right now but I think prices of these domains will rise to be in line with fundamentals eventually.