Just about the only sound heard on the streets of central Tokyo these days is the strange puttputt of the engines that drive the police department's chartered blimp.

With 10 officers on board peering down with binoculars, the blimp -- a throwback to another age in the capital of high-tech everything -- spends the daylight hours circling low overhead in search of anyone who has somehow got past the thousands of officers standing guard on the silent streets below.

In the name of security, Japanese authorities have all but closed the center of their crowded capital. Until Wednesday, it is the preserve of the seven-nation economic summit that Prime Minister Yasuhiro Nakasone convenes here on Sunday.

The Toyotas and Nissans that normally clog the streets have been replaced by squat gray armored vans parked to block streets that lead toward important buildings. Where normally there are throngs of pedestrians, only blue-uniformed men with staffs, visored helmets and steely gazes are seen.

SECURITY HAS frayed nerves from the start of Reagan's trip. In the Indonesian island of Bali, where Reagan stopped to consult with Southeast Asian leaders before coming here, Indonesian security forces complained about the U.S. Secret Service's insistence that it have the closest protective position to Reagan during a motorcade.

The Indonesians argued that their security forces have plenty of prowess, citing their storming of a hijacked plane in Thailand in which they freed all the passengers and killed the hijackers with the loss of only two of their own men.

Their feat went unnoticed in the United States, they said, because it occurred March 30, 1981 -- the day Reagan was shot in Washington.

WHITE HOUSE reporters coming to cover the summit got their first dose of the charged atmosphere a few minutes after they stepped off their jet at Haneda Airport. Waiting to view the arrival of President Reagan, they were shoved out of the way by brusque security officers.

It was, for the Japanese, a summit tradition. At a routine briefing today, presidential spokesman Larry Speakes opened with what seemed to be a precise account of the incident. But, in fact, he was reading from the memoirs of Carter administration spokesman Jody Powell describing a similar scene at the airport at the last Tokyo summit, in 1979.

AMONG THE MANY obliged to suffer for the Tokyo summit's sake are the regular guests at the 2,057-room New Otani Hotel and the hotel's owners.

On April 30, at the government's request, everyone not connected with the summit was moved out to turn the hotel, located next to the government guest house where the summit will take place, into headquarters for the European delegations and press.

The problem is that the newcomers will fill only about 70 percent of the rooms in a holiday season when it is normally packed. The summit also will rule out the 20 to 30 catered parties that normally occur there daily at an average of $230 per head. The hotel is being left to swallow a loss of between $3.5 million and $5.3 million in the name of international harmony.

"On the point of profits, my president was not pleased," said hotel spokeswoman Kazuko Takahashi. "But we are pleased to help a big event held by the Japanese government."