The 6 (six) in the date 1964 looks to be larger than the other three numbers on the obverse of the coin. Is this an error ? Any thoughts... To be honest I feel the 4 is also a bit bigger than as well but not as much as the number six. On the reverse side, I also feel the I and C in America seem somewhat bigger ?
If you've a ruler you can measure them. However I think if you do you're going to find they're not very far off.
…Your post title says quarter…obviously it is a nickel. …And as @paddyman98 opined, smooshy. The 6 and 4 bore more of the brunt of circulation wear than did the 1 and 9, although you can see it also on the right side of the 9. When the devices flatten from wear it can make them seem larger…imo…Spark