The U.S. IS a country. However, the largest state in the U.S. is Alaska followed by Texas.
The greatest factor of any positive integer is the number itself.
There are no countries in the USA as the USA is a country itself. Perhaps you mean county? The largest county in the USA is San Bernardino County. Perhaps you mean state? Alaska is the largest state in the USA. Perhaps you mean territory? Puerto Rico is the largest territory in the USA.
The number itself
The biggest factor of 56 besides itself is 28.
Itself
Itself
The biggest city in Luxembourg is itself called Luxembourg.
Texas is the second largest state in the u.s
The biggest island in Cuba is Cuba. Cuba is an island itself.
Malappuram Itself.
None. Hawaii is in the middle of the ocean by itself and Alaska shares a border with Canada.