543

543 = 3 x 181.

543 is a number whose square (543² = 294,849) and cube (543³ = 160,103,007) use different digits.

543 is a number that cannot be written as the sum of three squares.

543 is a number n such that n² has the property that the sum of its digits and the product of its digits are nonzero squares: 543² = 294849; 2 + 9 + 4 + 8 + 4 + 9 = 36 = 36²; 2 x 9 x 4 x 8 x 4 x 9 = 20736 = 144².

543 Charlotte is an asteroid discovered in 1904.

Source: What’s Special About This Number?