What are the physical features of a Númenorean?

The Númenóreans were tall. Adult males were normally around 6′4″ or so (2 rangar in Númenórean linear measure), but some individuals were taller. Elendil the Tall was supposedly 2–1/2 rangar, or 7′11″ tall. Númenor was a prosperous realm with advanced health care, so I assume that most Númenóreans were well grown and healthy.

The Númenóreans were descended from the three houses of the Edain. While people of Númenórean descent in LotR are described as dark haired with grey eyes and pale skin, the population of Númenor itself included blue-eyed blonds as well, descendants of the House of Hador (e.g., Tar-Aldarion was blond). The populace also included descendants of the House of Haleth, so there may have been some people with browner skin and eye coloring. The original population of Númenor also included some Drúedain, called Woses in the Third Age. (Ghân-buri-Ghân in LotR was one of the Woses.) The Drúedain living in Númenor started to emigrate from the island around the reign of Tar-Aldarion and were all gone by the time of the Downfall.

The people of Númenor were long lived. At the beginning of the Second Age the lifespan of an ordinary Númenórean seems to have been around 210-240 years; they enjoyed a period of vigor three times that of the Men of Middle-earth. Erendis wife of Tar-Aldarion had felt the approach of old age before her death by drowning at age 214. Members of the royal house lived to around 400, more or less, at least to the reign of Tar-Telemmaitë (2136–2526), who died at age 390. After his reign the distinctions between royalty and ordinary people, in lifespan as well as other attributes, began to grow less. Tar-Ardamin (SA 2816–2899) was the first ruler to die before age 300. Tar-Palantir, the last Númenórean ruler to die of natural causes, lived to age 220.