2421

2421 is a natural number that lies between 2420 and 2422. In decimal notation it is odd and composite. Its prime factorization is 3^2 × 269, so its divisors are 1, 3, 9, 269, 807, and 2421. The sum of its digits is 9, and 2421 is divisible by 9, which makes it a Harshad number in base 10. The sum of its proper divisors is 1089, which is less than 2421, so 2421 is a deficient number. It is not a prime, not a square, and not a triangular number.

In calendars and culture, 2421 CE would be a year in the distant future; there are no widely noted historical events associated with this year.

In classification and cataloging, 2421 is sometimes used as an identifier in systems that assign sequential numbers to items, such as model numbers, part numbers, or registry entries. It may also appear as a numerical designation in routes, flight numbers, or postal codes, depending on the country.