7421

7421 is a natural number that follows 7420 and precedes 7422. It is an odd integer and, in decimal representation, consists of the digits 7, 4, 2, and 1.

In number theory, 7421 is the product of two primes, 41 and 181, making it a semiprime. Its positive divisors are 1, 41, 181, and 7421. Therefore the number of divisors is 4. The Euler totient function yields φ(7421) = (41 − 1) × (181 − 1) = 40 × 180 = 7200, and the sum of all divisors is σ(7421) = (1 + 41) × (1 + 181) = 42 × 182 = 7644. Since σ(7421) < 2 × 7421, 7421 is a deficient number.

Beyond pure mathematics, 7421 can appear as an identifying number in various contexts (for example, as a catalog, part, or incident number). The specific meaning depends on the system or domain using the designation. In educational settings, 7421 may be used as an illustrative example of semiprimes, divisor functions, and related concepts.