In a recent study J. Geng, W. Zhou, P. Skelton, W. Yue, I. Kinloch, A.Windle, and B. Johnson, J. Am. Chem. Soc. 1302527 (2008)., it was demonstrated that exceptionally long fullerene nanowires, with a length-to-width aspect ratio as large as ~3000-5000, can be grown from 1,2,4-trimethylbenzene solution of C₆₀. We have performed a thorough theoretical analysis aiming at gaining an in-depth understanding of the exceptionally large aspect ratio of C₆₀-based nanowires. By accounting for different interactions in the system we have calculated the structures of the unit cell and determined the role of the fullerene and of the solvent molecules in the crystallization process of the nanowires. We have calculated the adhesion energy of C₆₀ molecules to the nanowire surface, and on the basis of this explained the growth anisotropy of the crystal. To get a more profound understanding of the nanowire growth mechanism we have also considered the influence of electron polarization on the growth anisotropy and studied the possible polymerization reactions occurred between the C₆₀ and the solvent molecules.