9821

9821 is a number that appears in various contexts, including astronomy, mathematics, and popular culture. One of its most notable appearances is in the field of astronomy, where it is associated with the minor planet designated as 9821 Elst-Pizarro. This asteroid was discovered on September 24, 1989, by Belgian astronomers Eric Walter Elst and Guido Pizarro. It is notable for being a member of the Apollo group of near-Earth asteroids, which means it has an orbit that crosses Earth's path. The asteroid has an estimated diameter of about 1.5 kilometers and is classified as a potentially hazardous object due to its size and proximity to Earth.

In mathematics, 9821 is a composite number, meaning it has divisors other than 1 and itself. Its prime factorization is 3 × 7 × 13 × 37. The number also appears in various sequences and problems, though it does not hold any particularly unique mathematical significance.

In popular culture, 9821 has been referenced in a few contexts, including as a code or identifier in fictional works. For example, it has been mentioned in some science fiction stories and online forums as a placeholder or a unique identifier for objects or characters. Its use in these contexts is largely arbitrary and not tied to any specific meaning beyond its numerical value.

Overall, 9821 is primarily recognized for its association with the asteroid 9821 Elst-Pizarro, which remains an object of interest in planetary science due to its orbit and potential risks to Earth.