Why aren't the masses of all nuclei exact integer multiples of the mass of a single nucleion?

Masses of many atoms are close to integral multiple of the mass of an

Why the mass of the nucleus is less than the sum of masses of the nucleons?

Why is nuclear density same for all nuclei?

Assertion : In a nuclear process energy is released if total binding energy of daughter nuclei is more than the total binding energy of parent nuclei. Reason: If energy is released then total mass of daughter nuclei is less than the total mass of parent nuclei.

If in a nuclear fusion process the masses of the fusing nuclei be m_(1) and m_(2) and the mass of the resuktant nucleus be m_(3) , then

The mass number of a nucleus is 216 .The size of the nuclei of the order of

Statement-1: Density of nuclear matter is same for all nuclei Statement-2: Density has nothing to do with mass and size of nucleus.

Time period of a particle in SHM depends on the force constant k and mass m of the particle T = 2psqrt((m)/(k)) . A simple pendulum exeutes SHM approximately. Why then is the period of a pendulum independent of the mass of the pendulum ?