It has degree 4, with 5 vertices and 10 edges.
It has girth 3, diameter 1 and radius 1.
Its symmetry group has 120 elements.
It is not bipartite.
It is Hamiltonian.
It is symmetric.
It is 4-arc-transitive.
Its distance-list is 1,4.
K5 is the skeleton of {4,4}(2,1)
K5 is the skeleton of C5:{10,4}
For copyright details of Wikipedia image see Complete_graph_K5.svg.