Artistic representation of Ethereum block 524,287. This is a special block, because 524,287 is the 7th Marsenne prime, discovered by Pietro Cataldi in 1588 using trial division. Marsenne primes are prime numbers of the form 2^p - 1, where p is a prime number, in this case p = 19. As of Semptember 2019, only 51 Mersenne primes are known, and the largest known prime number 2^82,589,933 − 1 is a Mersenne prime. Curiously, Ethereum block 524,287 was mined on November 11, 2015, right in the middle of the first DevCon conference in London.