243 = 35, a perfect fifth power.
243 is the first number of the form pq where p and q are a twin prime pair (3, 5).
243 is the sum of the first three palindromic primes: 243 = 11 + 101 + 131.
243 is 3303 in base 4, 1433 in base 5, 1043 in base 6, 363 in base 8, 300 in base 9, 183 in base 12, and 113 in base 15.
243 Ida is a large, irregularly shaped asteroid. It was the second asteroid to be visited by a spacecraft and the first to be found to possess a satellite.
Source: Number Gossip
