243 (number) explained

243 (two hundred [and] forty-three) is the natural number following 242 and preceding 244.

Additionally, 243 is:

• the only 3-digit number that is a fifth power (3⁵).
• a perfect totient number.^[1]
• the sum of five consecutive prime numbers (41 + 43 + 47 + 53 + 59).
• an 82-gonal number.

Notes and References

1. Web site: Sloane's A082897 : Perfect totient numbers. The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. 2016-05-28.