The number 4997 comes from the "Xenophobia" release group, who dumped and released the ROM to the internet on February 22, 2009, shortly before the official US retail release date (March 22, 2009).
The gameplay of Pokémon Platinum involves exploring the Sinnoh region, catching and battling Pokémon, and thwarting the plans of various antagonistic teams. Key features include: pokemon platinum rom 4997