I know I do have a middle name as it is listed in my birth certificate and I have many documents from my childhood that include it (e.g. school records), it is also used for elections but it was never included in my national identity card or passport.
I'm an Austrian citizen and actually have travelled around many countries where it could have caused problems, but I didn't have any trouble so far, not even in the US. However, I'm planning to travel to Russia and Belarus soon, and I don't know about those countries.
I have a valid national identity card and passport that both show my name without the middle name.
Can this affect any travel, specifically to Russia or Belarus? Do other countries know or care about my middle name?