Cornell University doesn't publish a single, university-wide student-to-faculty ratio. The ratio varies significantly depending on the college (e.g., College of Arts and Sciences, Engineering, etc.) and even the specific department within a college. Some departments, particularly in smaller, more specialized programs, will have much lower student-to-faculty ratios than larger ones.
To get a sense of the ratio, you'd need to look at individual college or department websites, or contact those departments directly. Cornell's overall faculty-to-student ratio is often cited around 6:1 or slightly better, but that's an average and can be misleading.