Considering only natural numbers, besides the obvious 1 x 671, the only combination of two numbers that multiplies into 671 is 11 x 61 (or 61 x 11, of course).
671, 1342, 2013, 2684, 3355, 4026 +671 . . .
It is: 671 = DCLXXI
1, 11, 61, 671
No - 671/2 = 335.5
83.875
0.1431
2314 + 671 = 2985
0.0373
10 + 671 = 681
0.0343
It is: 671 = DCLXXI in Roman numerals
671 x 5280 = 3,542,880