3937
The sum of consecutive numbers (starting with 1), is the square of the number of terms you sum, in this case 1600. 1600^2 = 2,560,000
The sum of all the positive factors of 12 is 28.
The sum of the positive whole-number factors of 30 is 72.
105 is the sum
105 is the sum
The odd factors of 70 are: 1, 5, 7, and 35. The sum of these factors is 48.
32
28
The factors of 1600 are: 1, 2, 4, 5, 8, 10, 16, 20, 25, 32, 40, 50, 64, 80, 100, 160, 200, 320, 400, 800, 1600
1601
The sum is 144 if 60 is included, 84 if not.
31