Is Qtum ERC20?

Excuse me, I've been hearing a lot about Qtum and ERC20 tokens lately. Could you clarify if Qtum is, in fact, an ERC20 token? My understanding is that ERC20 is a standard interface for tokens on the Ethereum blockchain, but Qtum seems to operate on its own blockchain. Is there any interoperability or compatibility between Qtum and ERC20 tokens? Or are they completely separate entities? I'm just trying to get a clearer picture of how these two concepts relate, if at all. Thank you for your clarification.