Two hundred eighty-four (284, CCLXXXIV) is the natural number following 283 and preceding 285. Its divisors are 1, 2, 4, 71, and 142, making it an amicable number with 220; and its factorization is
There is no answer to the equation φ(x) = 284, making 284 a nontotient.
Lear produced a number of similar albums from the 1850s onwards, the item here described being the second in a series that included works on Greece, Corsica, Albania, and the Ionian Islands, the last issued in 1870.
Six of the plates (including one map) are stained in the margin, this being most severe on the and#34;Pass of Canaloand#34; plate.
The other plates have some foxing to the margins, although a number are quite clean and unmarked.