Integers are still only 32 bits. There’s a class which effectively represents 64-bit integers (https://www.rdocumentation.org/packages/csvread/versions/1.2...) as well as arbitrary-sized (https://cran.r-project.org/web/packages/gmp/index.html, https://www.rdocumentation.org/packages/gmp/versions/0.7-4/t...). I will say there are a few pitfalls where the integer bits are unexpectedly converted to something else, but it’s workable.