650

650 can refer to several different concepts, depending on the context. As a natural number, it is an even, composite integer. Its prime factorization is 2 × 5^2 × 13. In Roman numerals, 650 is written as DCL, and in binary it is 1010001010.

In calendar usage, 650 refers to the year 650 CE, which lies in the seventh century. This period saw ongoing developments across various regions, including Tang China and the early Islamic Caliphate, with different regions experiencing distinct historical trajectories.

Geographically, 650 is an area code in the North American Numbering Plan. It serves the San Francisco Peninsula in California, covering parts of San Mateo County and adjacent communities such as Palo Alto, Mountain View, Redwood City, and San Mateo, among others.

In technology, the IBM 650 Magnetic Drum Data-Processing Machine was a widely used mainframe introduced in the mid-1950s. It played a significant role in the early commercial use of computers and is often cited as one of the first mass-produced business computers.

In science and engineering, 650 nanometers is a wavelength of light in the visible red region. This wavelength is commonly associated with red displays, lighting applications, and certain red laser diodes, reflecting its practical use in optics and electronics.