Pixel size, Equivalent pixel densities aps-c and full frame

[normadel]

I have an EOS 60D 18 Megapixels and a 6D that's  20 Megapixaels.  I'll make two statements that I think are true:

1. The 60D has higher pixel density than the 6D.

2. The 6D's pixels are larger.

Right?

What full-frame megapixel count would give equivalent pixel density to the aps-c 18 MP sensor? Is there a simple ratio? Like 1.6?

[jrhoffman75]

Ratio between 60D and 6D pixel density is 2.3. Multiply 20MP for 6D by the ratio equals 46MP. 

As a check, pixel density of 45MP EOS R5 is 5.21.

[ebiggs1]

I will add a .2 difference is not going to make a big difference. Probably not even detectable unless you are at extreme enlargements. Your statements one and two are correct but not significant in this case.