Mass is a measure of a bodies tendency to resist a change in motion, also known as inertia. So, I guess, in a way, the answer to your question is yes, kind of. The more matter a body consists of the more mass it will have. It would probably be best to separate the two terms in your mind and vocabulary tho...
mass
No. E=mc2 is a formula. Energy equals mass times the speed of light squared.
E (Energy) equals M (Mass) times C2 (speed of light square)
massM = mass
E = mc^(2) 'E' is the Energy 'm' is the 'mass' 'c' is the 'speed of light in a vacuum. in nuclear disintegration, when an atom disintegrates into two smaller atoms, there is a difference in the 'mass(m)', Miniscule though it may be, but when multiplied to the speed of light squared , there is million if not billions of Joules of energy, which is released. The speed of light in a vacuum is 3.8 x 10^(8) J . Hence c^(2) = [3.8 x 10^(8)] = 1.44 x 10^(17) (m/s)^(2)
There is no sum of e=mc2, it is an equation concerning matter and energy. e=mc2 stands for: Energy equals mass times the velocity of light squared. E = M C 2
m = e*c-2
zero mass = zero energy
Mass-energy equivalence
Some mass is "lost" during nuclear fusion and E = mc2 gives the amount of energy that this "lost" mass will be equal to.
e = mc2 is an equation, it has no size of its own. The value of e (energy) depends on the amount of mass (m) and conversely. The smaller the mass is the smaller the amount of energy.
Mass Energy.