Thanks for gurus' reply!
Of course, data in my programme isn't a simple 1024**4, I just want to say the number is too big to wrap in 32bit.
bigint I'll study soon seems a straightforward way to solve this issue, but I prefer BrowserUk 's trick since I don't need to load a big module.
I am trying to improve my English skills, if you see a mistake please feel free to reply or /msg me a correction