This is purely an indictment of modern mathematics education. Anyone doing ordinary high school math should have had their ears full of Euler's contributions for at least a couple of years towards the end. Math teachers who don't mention Euler need to be put onto a mock Königsberg and forced to search for a solution.

Most people can't name any mathematicians, but amongst those that can I think he's top 5, behind more famous names like Newton, Archimedes and Euclid

And Gauss.

Sure, I didn't really mean the general public but meant scientific/mathematically oriented public. When I studied math in college, I found Euler everywhere to the point that it was hard not to stop and wonder how the hell this guy had so many fundamental discoveries. By contrast, I have awareness of present day figures like Tao and Erdos, but I don't really understand their work and perceive it to be specialized enough that it is unlikely to be widely understood in the way that say e^(pi * i) + 1 = 0 is.