The labeling of a graph, we mean assign some integers to the vertices or edges (or both) of the graph. Here the vertices of the graph are labeled with oblong numbers and the edges are labeled with mean of the absolute difference of the end vertex values. Here the greatest common incidence number (gcin) of a vertex of degree greater than one is defined as the greatest common divisor of the labels of the incident edges. If the gcin of each vertex of degree greater than one is 1, then the graph admits oblong difference mean prime labeling. Here we investigate some planar graphs for oblong difference mean prime labeling.

Keywords- Graph labeling, oblong numbers, prime graphs, prime labeling, planar graphs.