Bluebulb Projects' The Measure of Things presents:
540 is about two-thirds the number of Population of Vatican City.
In other words, it's 0.641 times the count of Population of Vatican City, and the count of Population of Vatican City is 1.56 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)