3.91 = 4
391 rounded to the nearest tens place is 390
400
390
0.8
391.0
400
391 is a composite number. 391 = 17 * 23 A prime number is a whole number that only has two factors which are itself and one. A composite number has factors in addition to one and itself.
390
Factors of 391: 1, 17, 23, and 391.Factors of 696: 1, 2, 3, 4, 6, 8, 12, 24, 29, 58, 87, 116, 174, 232, 348, and 696.The only whole number that goes into both 391 and 696 evenly is ' 1 ' .
100 + 391 = 491
391 A number and its additive inverse must equal zero.
400.