If the product of an integer a and 1260 is a complete square number, then the minimum value of a is? What is the square number?

If the product of an integer a and 1260 is a complete square number, then the minimum value of a is? What is the square number?

one thousand two hundred and sixty
=2×630
=2×3×210
=2×3×3×70
=2×3×3×2×35
=6²×35
1260×A
=6²×35×A
=(6A)²
A=35