The city of Izhevsk, capital of the Udmurt Autonomous Socialist Republic, will be renamed after the late defense minister Dmitri Ustinov, the Soviet news agency Tass announced today.

Listed as having a population of 456,000 in the 1972 census, Izhevsk was founded in 1760, and was made capital of the region, also known as Udmurtia, in 1934. Udmurtia is one of the 16 republics within the Russian Federated Republic, the largest of the U.S.S.R.'s socialist republics.

Tass also announced today that a naval vessel, a military unit, a factory and streets in Moscow and other cities would be renamed after Ustinov.

Changing names of cities is not unusual in the Soviet Union: The city of Rybinsk was renamed for the late Soviet leader Yuri Andropov a month after his death in February 1984.

But how and why a particular city is picked, or volunteers, for the honor is not explained. In the case of Izhevsk, there is no apparent connection with Ustinov, one of the most powerful men in the Kremlin, who died Dec. 20 at age 76.

Located in central Russia, 620 miles east of Moscow, Izhevsk is an unusual choice given its status as capital of a republic and home of one of the Soviet Union's smallest ethnic "nationalities."

Udmurtia's 1980 population was 1.5 million, but according to earlier figures, Russians outnumber the Udmurts, once known as Votyaks, by 2 to 1. In 1983, the republic celebrated the 425th anniversary of its "voluntary affiliation" with Russia.

Remaking Izhevsk into Ustinov will not be the first name change for the region. After the Russian revolution, the republic was first called Votskaya, its name in czarist times, but its name was revised to Udmurtia in 1932.