Common ammont of HP for all PvE is about 17-19k HP, depending on group DPS, you personal survivobility, etc.
If you were asking about the bosses HP, I don't really remember, but I'm sure that if you and your groupmates have 7k+ DPS in solo target, you can do all todays PvE content. But actual top DPS now is much higher: 15k+ and up to 20k+ for mele-magica-DK-Dunmer.