891×21

891×21 denotes the product of the integers 891 and 21. It is a straightforward arithmetic multiplication often used to illustrate basic multiplication and factorization.

Calculation: 891×21 = 891×20 + 891 = 17,820 + 891 = 18,711.

Factorization view: 891 = 3^4 × 11 and 21 = 3 × 7, so the product equals 3^5 × 7 × 11 = 18,711.

Properties and verification: The result is an odd integer, and its digit sum is 1+8+7+1+1 = 18, which confirms divisibility by 9; indeed 18,711 ÷ 9 = 2,079. It is also divisible by 7 and 11 due to the factorization above.