The Soviet claim was 83k killed 609k captured. However, I may be wrong in my assumption that the IJA fought to the last man in all other campaigns. Thanks
Japan surrendered, so they stopped fighting.
On the 14th of August, 1945, the Japanese government contacted the Allies and offered to accept the Potsdam surrender terms (Hirohito's recorded surrender message to the Japanese people was recorded late at night on the 14th and broadcast the next day). In the evening, Emperor Hirohito ordered a cease-fire, which the High Command relayed to units in the field. The commander of the Kwantung Army, General Yamada, ordered the Kwantung Army to continue fighting. In response, the Soviets continued their offensive. With the Soviet offensive continuing, the original cease-fire orders failed to reach all units, and some units which received the order continued to fight on their own initiative. Other units continued to fight due to Yamada's order. So, in general, the fighting continued in Manchuria, and there were few surrenders of Japanese forces (Manchurian forces surrendered much more readily (or deserted en masse), from the beginning of the Soviet attack).
The Kwantung Army surrendered on the 18th, and broadcast cease-fire orders to its units. Japanese forces engaged with the Soviets largely surrendered on the 18th and the 19th. Thus, Japanese resistance mostly ceased by the 19th. Some units didn't receive the surrender orders, or refused to surrender despite the orders, and continued to fight. Most forces engaged with the Soviets surrendered in the next few days, but some units continued to resist until the 30th of August.
As the forces fighting the Soviets surrendered (mostly on the 18th and 19th), the Soviets took about 50-60,000 prisoners in the main surrenders. The bulk of the POWs, that is, the other half-million+, were taken prisoner after the surrender, and had already laid down their arms. Approximately 2 million Japanese civilians were also held by the Soviets. The civilians were repatriated or released to make their own way back to Japan. Most of the military prisoners were taken to the Soviet Union for forced labour. There is disagreement between the Russian government and the Japanese government over the status of these prisoners. The Russian government, as the Soviet government did beforehand, describes them as POWs. The Japanese government considers them internees, because they were captured after the war had ended (illegally captured, according to the Japanese government).
Had Japan not surrendered, far fewer POWs would have been taken. Not almost none, but far fewer. Note that approximately 10% of the Japanese forces on Okinawa surrendered (and a larger fraction of the Okinawan conscripts) - they didn't fight to the last man.
The Japanese surrenders are discusses in the classic study of the Soviet invasion of Manchuria:
and my estimate of 50-60,000 POWs taken as Japanese forces fighting the Soviets surrendered comes from the numbers given by Glantz.