What are the 3 composite numbers that have 3 factors?

Composite numbers having three factors are the squares of all prime numbers. Examples are 4 (1 2 4), 9 (1 3 9), 25 (1 5 25), 49 (1 7 49), 121 (1 11 121), 169 (1 13 169), 289 (1 17 289), 361 (1 19 361), etc.