There's ample evidence from the time that rather than take credit, as _many_ unethical scientists have tried (*cough Newton), Euler was quite the opposite. I think one of his strengths was in his prolific collaborations actually, or taking up questions others sent to him which he did not need to work on, but would out of curiosity or decency.

I get why someone not familiar with him may think this, but when I think of the word "genius" only this man, von Neumann, Ramunajan and Grothendieck come to my mind. They simply saw the world differently.