  Let $G$ be a finite group, $\pi(G)$ be the set of prime divisors dividing the
order of $G$ and $\pi_e(G)$ (spectrum) denote the set of element orders of $G$.
We define $w_o(G)$ = $|\pi(G)|$ the width of order of $G$ and $w_s(G)$ =
max$\{|{\pi}(k)| | k \in \pi_e(G)\}$ the width of spectrum of $G$. In this
paper, we discuss the cases of $w_o(G)$ and $w_s(G)$ are small, prove several
new results and give a survey about the two widths of groups.
