9721

9721 is a natural number that follows 9720 and precedes 9722. In mathematics, 9721 is a prime number, meaning it has only two distinct positive divisors: 1 and itself. A standard primality check shows no divisors among primes up to 97, and since the square root of 9721 is about 98.6, this confirms its primality.

9721 is an odd four‑digit integer with a decimal digit sum of 19, giving a digital root of 1. It is not divisible by 2, 3, or 5, and it is not a perfect square (since 98^2 = 9604 and 99^2 = 9801). In other bases, it has representations such as binary 10010111111001, hexadecimal 0x25F9, and octal 22771.

As a four‑digit prime, 9721 appears in general discussions of primality, base conversion, and elementary number theory. Its status as a prime makes it a convenient example for demonstrating primality tests and conversions between decimal, binary, hexadecimal, and octal representations.