225 = (15)2
2*2*5=20
3 digits in 225
81
121
It can have up to 5 digits.
81
Every square of a 4 digit number has more than four digits.
81
1
121
The only three-digit number that fits the criteria of being a square number and having a product of its digits equal to two is 128. This is because 128 is a square number (11^2 = 121, 12^2 = 144) and the product of its digits (1 x 2 x 8) equals 16, which is not equal to two. Therefore, there is no three-digit number that meets all the given conditions.
It can have up to 5 digits.
81
Six.
49
You had me until "product." The product of 4 digits can't be prime.
Every square of a 4 digit number has more than four digits.
81...........
362x(3x6)