Yes, but not in Perl. Perl stores data in internal types, such as SVs, NVs, and IVs. Since it also tracks other things, such as any magic applied to a variable and the number of references pointing to it, there's not a one to one correspondence between numbers and bytes. Besides that, with Unicode, it's usually not very helpful to think about bytes anyway.

If you could outline what you're attempting to accomplish, perhaps someone would tell you a more Perlish way.