Suppose, G is a group of order $n$.
Is there a name (or an easy criterion) for the property that for every divisor $d|n$, there is a normal subgroup of order $d$ ?
The abelian groups and the p-groups have this property, but other groups satisfy the property as well. The dihedral groups (excluding the 2-groups) do not have this property.
Yes, these are precisely the finite nilpotent groups.
This is because a finite group is nilpotent if and only if it has a unique - that is, normal - Sylow $p$-subgroup for each prime divisor $p$ of its order. And thus, the finite nilpotent groups are exactly the direct products of groups of prime-power order.