Here is my code -

#include<stdio.h>

int main()
{
    __int64 n;
    int m[100],i=0,j=0;

    printf("Enter the number\t");
    scanf("%lld",&n);

    if(n==1) {
        j=1;
        printf("Result is %d\n",j);
    }
    else if(n == 0) {
        j=10;
        printf("Result is %d\n",j);
    }
    else if(n < 10) {
        j=n;
        printf("Result is %d\n",j);
    }
    else
    {
        for(i=9;i>1;i--)
        {
            if(n%i == 0)
            {
                n=n/i;
                m[j++]=i;
                i++;
            }
        }
        if(n!=1) {
            j=-1;
            printf("Result is %d\n",j);
        }
        else
        {
            for(i=j-1;i>=0;i--)
                printf("%d",m[i]);
        }
    }

    return 0;
}

It gives the correct output, i have preformed following test cases --

Input->output
0 -> 10
1 -> 1
2 -> 2
3 -> 3
4 -> 4
5 -> 5
6 -> 6
7 -> 7
8 -> 8
9 -> 9
10 -> 25
11 -> -1
12 -> 26
13 -> -1
14 -> 27
15 -> 35
16 -> 28
17 -> -1
18 -> 29
19 -> -1
20 -> 45
21 -> 37
22 -> -1
23 -> -1
24 -> 38
25 -> 55
26 -> -1
27 -> 39
28 -> 47
29 -> -1
30 -> 56
31 -> -1
32 -> 48
33 -> -1
34 -> -1
35 -> 57
36 -> 49
37 -> -1
38 -> -1
39 -> -1
40 -> 58
41 -> -1
42 -> 67
43 -> -1
44 -> -1
45 -> 59
46 -> -1
47 -> -1
48 -> 68
49 -> 77
50 -> 255
51 -> -1
52 -> -1
53 -> -1
54 -> 69
55 -> -1
56 -> 78
57 -> -1
58 -> -1
59 -> -1
60 -> 256
61 -> -1
62 -> -1
63 -> 79
64 -> 88
65 -> -1
66 -> -1
67 -> -1
68 -> -1
69 -> -1
70 -> 257
71 -> -1
72 -> 89
73 -> -1
74 -> -1
75 -> 355
76 -> -1
77 -> -1
78 -> -1
79 -> -1
80 -> 258
81 -> 99
82 -> -1
83 -> -1
84 -> 267
85 -> -1
86 -> -1
87 -> -1
88 -> -1
89 -> -1
90 -> 259
91 -> -1
92 -> -1
93 -> -1
94 -> -1
95 -> -1
96 -> 268
97 -> -1
98 -> 277
99 -> -1
100 -> 455

still i am getting WA#1, I don't know what the hell is wrong in that. Can any body tell me, why am i getting WA#1??

No need to printf "Result is"!