Mathematician:Ivan Mikheevich Pervushin

Full name in Russian: Иван Михеевич Первушин.

Russian priest, who worked in number theory in his spare time.

Most famous for demonstrating the primality of the Mersenne number $$M_{61}$$, which then became known as Pervushin's number. Proved the following:
 * 1877: The Fermat number $$2^{2^{12}} + 1$$ is divisible by $$7 \times 2^{14} + 1$$, thus showing that $$F_{12}$$ is not prime;
 * 1878: The Fermat number $$2^{2^{23}} + 1$$ is divisible by $$5 \times 2^{25} + 1$$, thus showing that $$F_{23}$$ is not prime;
 * 1883: The Mersenne number $$M_{61}$$ is a Mersenne prime.

Nationality
Russian.

History

 * Born: January 21, 1827
 * 1852: Graduated from Kazan clerical academy, and became a priest in Zamaraevo.
 * 1883: Moved to Shadrinsk, where he wrote a paper ridiculing the local government.
 * 1887: Exiled to Mehonskoe as a result.
 * Died: June 29, 1900