It's about two-and-a-half times the number of Moons in our Solar System.
In other words, 390 is 2.67 times the count of Moons in our Solar System, and the count of Moons in our Solar System is 0.375 times that amount.(2015 figures) (confirmed moons only; dwarf planet satellites not included)
Astronomers and other scientists have confirmed the presence of 146 moons orbiting the major planets of our Solar System. About one third of those moons — 53 — are in orbit around the planet Saturn
It's about three times the number of Union Stations in the United States.
In other words, 390 is 2.89 times the count of Union Stations in the United States, and the count of Union Stations in the United States is 0.346 times that amount.(a.k.a. Union Terminal; a.k.a. Joint Station; a.k.a. Union Depot) (2016 figures)
Typically shared between multiple railroad companies and stations, there are about 135 "Union Stations" in the United States. Of these, the busiest station is Chicago Union Station, which handles 120,000 passengers each year.
It's about three-and-a-half times the number of Elements on the Periodic Table.
In other words, 390 is 3.31 times the count of Elements on the Periodic Table, and the count of Elements on the Periodic Table is 0.302 times that amount.(a.k.a. Periodic Table of the Elements, a.k.a chemical elements) (confirmed elements as of 2016)
From element number one, hydrogen, to element one-hundred eighteen, ununoctium, there are 118 confirmed elements on the Periodic Table. Ninety-four of the elements exist in nature, and the remaining twenty-four have only been synthesized in labs (not having occurred naturally in the time since scientists have begun researching them)
It's about four times the number of Wolves in Yellowstone National Park.
In other words, 390 is 3.75 times the count of Wolves in Yellowstone National Park, and the count of Wolves in Yellowstone National Park is 0.267 times that amount.(a.k.a. Henihco'oo; a.k.a. Héetíhco'oo) (December 2014 figures; Wyoming Park area)
As of the 2014 population count, there were 104 wolves living in Yellowstone National Park, in twelve packs. All of the wolves now living in the Park are thought to have descended from the 66 wolves (re)introduced into the Park in 1995-96.
It's about one-fourth the number of Golf Courses in Florida.
In other words, 390 is 0.2569 times the count of Golf Courses in Florida, and the count of Golf Courses in Florida is 3.893 times that amount.(2016 figures) (public and private)
The US state of Florida includes 1,518 golf courses in its 170,000 sq. km area. The state is also the home of the headquarters of the Professional Golfers' Association (PGA) of America, which boasts a membership of 28,000 professional golfers.
It's about four-and-a-half times the number of Keys on a Piano.
It's about five-and-a-half times the number of Submarines in the US Navy.