//question is like that if accept 120 then show 5 beczz 120=1*2*3*4*5=5;
130 then not possible
if 720 then show 6 beczz 720=1*2*3*4*5*6=6;
LOGIC:-
main()
{
int n,fact=1,i=2;
printf("enter number\n");
scanf("%d",&n);
while(fact<n)
{
fact=fact*i;
i++;
}
if(fact==n)
printf("reverse factorial of %d is %d", n,--i);
else
reverse not possible;
}