Laxey Wheel Laxey Wheel The Laxey Wheel (also known as Lady Isabella) is built into the hillside above the village of Laxey in the Isle of Man. It is the largest working waterwheel in the world. Designed by Robert Casement, the wheel has a diameter, is wide and revolves at approximately three revolutions per minute. It was built in 1854 to pump water from the Glen Mooar part of the Great Laxey Mines industrial complex. It was named "Lady Isabella" after the wife of Lieutenant Governor Charles Hope, who was the island's governor at that time. The 150th anniversary of the Lady
Largest known prime number Largest known prime number The largest known prime number () is 2 − 1, a number with 23,249,425 digits. It was found by the Great Internet Mersenne Prime Search (GIMPS) in 2017. Euclid proved that there is no largest prime number, and many mathematicians and hobbyists continue to search for large prime numbers. Many of the largest known primes are Mersenne primes. , the seven largest known primes are Mersenne primes. The last sixteen record primes were Mersenne primes. The fast Fourier transform implementation of the Lucas–Lehmer primality test for Mersenne numbers is fast compared to other known primality tests