This is a fundamental article reporting newly observed mathematical-computational manifestations in Quran. The Principle Variations (PVs) for the purpose of textual analysis will be defined and a Normal Book model based on the stochastic nature of human writing will be developed. It will be shown that chapter word frequencies in Quran fit into an exponential model, in sharp contrast to the uniform distribution model commonly observed for other books. In particular, a phenomenal cross diagonal characteristic of the PVs in Quran will be shown to completely distinguish its exponential structure from observed structures of the world literature. Graphical and Parametric effects of the exponential construct of Quran will be shown through logarithmic plots and Fourier analysis of its PVs. The couplings observed from its variations in addition to an independent analysis of the prime numbers point to π and e, as pillars of the mathematical construct of Quran. Computed parameters of a Stepwise Fourier analysis of the PVs in Quran, reveals a finely regulated Nineteen Based Fourier Structure (NBFS) highly sensitive to the textual manipulations. These observations seem sufficient to qualify Quran as a case of (Multifaceted) Mathematically Fully Constrained Writing (MFCW), a concept defined for the first time in this article. As its prime consequence, a MFCW Quran points to the nonhuman origin of the Arabic language. Interesting observations are also made through Fourier analyses of particular names which can be indicative of an astonishing futuristic vision of Quran. The importance of such mathematical investigations particularly from the MFCW point of view will be emphasized and some relevant future studies will also be outlined.