The time dilation formulas of both the specific relativity and the general relativity could be understood as children of a common expression that uses a factor dependent on the specific energy. Surprisingly when such factor is used to define the relativistic mass, the equation that arises is an extraordinary approximation of the mass and energy relation. An entangled mathematical perspective of both time and mass that opens up again the question of what their definition really is, and which are the factors that modify such variables.