births
January 21, 1827
Ivan Mikheevich Pervushin, Russian mathematician and theorist (died 1900)
Ivan Pervushin
Ivan Mikheevich Pervushin was a Russian clergyman and mathematician of the second half of the 19th century, known for his achievements in number theory. He discovered the ninth perfect number and its odd prime factor, the ninth Mersenne prime. Also, he proved that two Fermat numbers, the 12th and 23rd, were composite.