2205 times a natural number a, the product is a complete square number, then a is the minimum______ .

2205 times a natural number a, the product is a complete square number, then a is the minimum______ .

Since 2205 = 3 × 3 × 5 × 7 × 7 = 5 × 21 × 21, the minimum of a is 5, that is, the complete square number is 2205 × a = 5 × 5 × 21 × 21 = 1052 = 11025