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, Lysva, Perm, Russia
 * 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, Mehonskoe, Russia

Theorems and Definitions

 * Pervushin's Number