509

509 is a natural number that follows 508 and precedes 510. In mathematics, 509 is prime, and it is the 97th prime number. It can be expressed as the sum of two squares: 509 = 22^2 + 5^2.

In Roman numerals, 509 is written as DIX.

In history, 509 BCE is traditionally cited as the year the Roman Republic was established after the overthrow of the Roman monarchy led by Tarquin the Proud.

In the United States, 509 is an area code used in much of eastern Washington state, including Spokane, the Tri-Cities area (Kennewick, Pasco, Richland), Yakima, and Wenatchee.

In computing and networking, 509 is an unofficial HTTP status code used by some servers to indicate that bandwidth limits have been exceeded.

In military history, the 509th Composite Group was a United States Army Air Forces unit formed during World War II. It is best known for delivering the atomic bombs on Hiroshima and Nagasaki in 1945, operating B-29 aircraft from bases in the Pacific, notably Tinian.