284

284 = 2² x 71.

284 is a number that cannot be written as a sum of three squares.

284 = 2⁸ + 28.

284 and 220 form a pair of amicable numbers, the smallest amicable pair. Two numbers n and m are called an amicable pair if the sum of all positive divisors of n is equal to the sum of all positive divisors of m and both are equal to n + m.

The Greek mathematician Diophantus died in the year 284.

Source: Number Gossip