one factor of the mystery number is 7

the other factor is an odd number greater than 8 and less than 15
the mystery number is greater than 75
the sum of the digits of the mystery number is 10
what is the mystery number?
what is the missing factor????

m = mystery number

m = 7k
k is in {9,11,13}
m is now either 77 or 91
9+1=10

m = 91 and k=13