  The six-loop expansions of the renormalization-group functions of $\varphi^4$
$n$-vector model with cubic anisotropy are calculated within the minimal
subtraction (MS) scheme in $4 - \varepsilon$ dimensions. The $\varepsilon$
expansions for the cubic fixed point coordinates, critical exponents
corresponding to the cubic universality class and marginal order parameter
dimensionality $n_c$ separating different regimes of critical behavior are
presented. Since the $\varepsilon$ expansions are divergent numerical estimates
of the quantities of interest are obtained employing proper resummation
techniques. The numbers found are compared with their counterparts obtained
earlier within various field-theoretical approaches and by lattice
calculations. In particular, our analysis of $n_c$ strengthens the existing
arguments in favor of stability of the cubic fixed point in the physical case
$n = 3$.
