1.
five hundred (500)
The number 500.
五百 is 五 (five) + 百 (hundred). No sound change occurs — ひゃく stays as ひゃく after ご.
Sound changes in hundreds
The hundreds have irregular pronunciation for certain numbers:
Common expressions
Cultural note
The 五百円玉 is notable as the largest-denomination coin in regular circulation in Japan. It is commonly saved in 貯金箱 (piggy banks) as a form of casual savings known as 五百円玉貯金.