TOKYO -- Reaching the century mark remains a relative rarity for humans, but it is increasingly less so, and perhaps nowhere more than in rapidly aging Japan.

The number of Japanese who are at least 100 years old, known as centenarians, has reached 58,820, according to the latest government estimate, released every September to mark Respect-for-the-Aged Day, a national holiday that falls on Monday.

A Japanese woman is the oldest person in the world, 116-year-old Misao Okawa, according to Guinness World Records.

The oldest man is also Japanese, 111-year-old Sakari Momoi. Somewhat appropriately, one of the Japanese characters in Momoi's last name means "100," and his first name Sakari translates as flourishing or the prime of life.

Advances in health care are contributing to increased longevity in Japan and elsewhere. Japan now has 46.21 centenarians for every 100,000 people.