1156 is a perfect square. Its prime factorisation is 2² × 17². All factors are in pairs. But 2800 = 2⁵ × 5² × 7, which has unpaired 2s and a 7, so 2800 is not a perfect square.
1156 is a perfect square. Its prime factorisation is 2² × 17². All factors are in pairs. But 2800 = 2⁵ × 5² × 7, which has unpaired 2s and a 7, so 2800 is not a perfect square.