SHANGHAI (AFP) - The number of people killed by Typhoon Soudelor in China rose to 21 on Monday, the authorities said, with five more missing.

Four died on Monday as the storm - downgraded to a tropical depression by the China Meteorological Administration - battered the eastern province of Anhui, with two elderly people drowned and two killed in a car crash caused by a rockfall, local authorities said on social media.

In neighbouring Zhejiang province, 14 were killed and four missing, the official news agency Xinhua reported earlier, quoting local officials as saying that the dead and missing may have been washed away by floods or buried under ruined homes.

Further south, in Fujian province where the typhoon made landfall on Saturday night, three people were killed by a mudslide and one was missing after being swept away by floods in Ningde, the Fujian Daily reported.

The total direct economic losses in the two coastal provinces were estimated at around 8 billion yuan (S$1.8 billion), figures from state media showed.

Billed as the biggest typhoon of the year last week with winds of up to 230 kmh, Soudelor has since weakened.

It left six people dead in Taiwan - including twin sisters and their mother, who were all swept out to sea - and knocked out power to a record four million households on the island.

Some 379 people were injured by the storm in Taiwan, which saw rivers break their banks under torrential rain and towering waves pound the coastline.