Bluebulb Projects' The Measure of Things presents:
6,400 is about three times the number of Steps in the Sears Tower.
In other words, it's 3.035 times the count of Steps in the Sears Tower, and the count of Steps in the Sears Tower is 0.32950 times that amount.
(a.k.a. Willis Tower) (Chicago, Illinois) (steps per stairwell)