200

200 = 2³ x 5².

200 has two representations as a sum of two squares: 200 = 2² + 14² = 10² + 10².

200 is a divisor of 49² - 1.

200 is the smallest unprimeable number. It cannot be turned into a prime number by changing just one of its digits to any other digit.

200 is 404 in base 7 and 242 in base 9.

An ice hockey rink is 200 feet long and 85 feet wide. Olympic-sized rinks are 100 feet wide.

Source: Number Gossip