12 978 189

12978189 = 3² x 7² x 29429.

12978189 has a representation as a sum of two squares: 12978189 = 483² + 3570².

12 978 189 is the number of decimal digits in the world’s largest known prime number, discovered on a UCLA computer on Aug. 23, 2008, as part of a 12-year-old, worldwide computing project called the Great Internet Mersenne Prime Search (GIMPS).

This number is the 45th known Mersenne prime, 2^43112609 – 1.

Marin Mersenne (1588–1648)

Source: Great Internet Mersenne Prime Search.
Image: Courtesy of Loci: Convergence