163821

163,821 is a natural number that lies between 163,820 and 163,822. It is odd and composite.

Its prime factorization is 163,821 = 3 × 7 × 29 × 269. Because all prime factors appear to the first power, the number is squarefree and has 16 positive divisors. The sum of its divisors is 259,200. The number is not a perfect square or cube.

In modular arithmetic, 163,821 is divisible by 3 and is congruent to 1 modulo 4 and 5 modulo 8. The digital root of the number is 3, since the sum of its digits (1 + 6 + 3 + 8 + 2 + 1) equals 21, which reduces to 3.

The factorization reveals a mix of small and relatively larger primes, with no repeated factors, making 163,821 a representative example of a squarefree composite number with a moderately large prime factor. Its properties are primarily of interest in elementary number theory, where factorization, divisor counts, and modular relationships are studied. There are no widely noted applications or notable historical associations tied specifically to the number 163,821.