1000

1000 = 2 x 2 x 2 x 5 x 5 x 5. 1000 is a perfect cube.

1000 can be expressed using the first three primes: 2³ x 5³.

The 147th prime (853) plus 147 equals 1000.

2⁹⁹⁹ + 1239 is the smallest 1000-bit prime.

1000 is 2626 in base 7. It is 1331 in base 9.

1000 has two representations as a sum of two squares: 1000 = 10² + 30² = 18² + 26².

T-1000 was the shape-changing robot from the 1991 film Terminator 2: Judgment Day.

Source: Prime Curios!