1145

1145 = 5 x 229.

1145 has two representations as a sum of two squares: 1145 = 11² + 32² = 19² + 28².

1145 is the hypotenuse of two Pythagorean triples: 1145² = 423² + 1064² = 704² + 903².

1145, 1147 (31 x 37), and 1149 (3 x 383) are each semiprimes, the product of two primes.

Halley's Comet appeared in the skies in the year 1145.

Source: WolframAlpha