Not sure what your definition of factorial is. But with the usual definition, the sum is,
0!+1!+2!+3!+4! ... = 1+1+2+6+24+.... = Ei(1)/e = .69...
where Ei is the exponential integral function and e is Euler's number. You can compute a few terms to see how it converges :)
To generate the sum of the factorial series nearly as fast the last factorial,
1+1+2+6+24+... = 1+1(1+2(1+3(1+...+14(1+15)...)))
The answer is 120.
1 + 3 + 5 + 15 = 24
Six.
The sum of the factors of any negative number is zero.
The factors of 225 are: 1, 3, 5, 9, 15, 25, 45, 75, 225. The sum of the factors is: 403
Factors of 15 are: 1 3 5 and 15 of which 3 and 5 are prime factors
The factors of 15 are: 1, 3, 5, and 15.The prime factors of 15 are: 3 and 5.The factors of 21 are: 1, 3, 7, and 21.The prime factors of 21 are: 3 and 7.
1 + 15 + 3 + 5 = 24
1, 3, 5, 9, 15, 45 (sum = 78).
13
5 and 3.
Six.
The Answer is 8 because... 1+2+4+8=15
303
13 and 2 12 and 3
60
12
2 and 15 5 and 12
1 + 3 + 5 + 15 = 24