Bluebulb Projects' The Measure of Things presents:
4,500 is about five-and-a-half times the number of Population of Vatican City
In other words, it's 5.340 times the count of Population of Vatican City, and the count of Population of Vatican City is 0.1870 times that amount.
(a.k.a. Vatican City State, a.k.a. Stato della Città del Vaticano
, a.k.a. Status Civitatis Vaticanae
) (Rome, Italy) (2014 estimates; permanent residents only)