TOKYO — Emperor Akihito celebrated his 77th birthday Thursday and urged Japan to pay heed to the needs of the elderly, as the number of older people in the country rapidly grows.

Akihito greeted thousands of well-wishers waving Japanese flags from a balcony at the Imperial Palace in Tokyo. Empress Michiko and other royal family members — including Akihito’s eldest son Crown Prince Naruhito and his wife Crown Princess Masako — appeared on the balcony.

Akihito has cut back on official duties because of health reasons. He did not make any foreign trips this year. The emperor underwent an operation for prostate cancer in 2003, and the Imperial Household Agency says he has been undergoing hormonal therapy to prevent its recurrence.

At a palace news conference Monday, Akihito also said that he has hearing problems.

"With regard to aging, I have become somewhat hard of hearing so when I receive people, I ask … them to try to talk to me in a louder voice," the emperor said.

He said he hopes people will be more attentive to the elderly, including more attention paid to ensure buildings and towns are better equipped to serve their needs.

"In our society today, where the aging population continues to grow, it is my sincere hope that there will be further understanding of the needs of the elderly," Akihito said.

Japan has long prided itself on its citizens’ long life spans. Government data for 2009 showed average life expectancy was about 86 1/2 years for women and 79 1/2 for men.

Japan also is one of the world’s most rapidly aging countries. Japanese who are 65 and older hit a record 22.7 percent of the population last year.