Find the greatest three digit prime number where each of the digits is prime and the sum of all three digits is also prime

The number is: 775

Step-by-step explanation:

The prime numbers from 1-9 are: 2,3,5,7

To form the greatest three digit prime number where each of the digits is prime and the sum of all three digits is also prime:

      so we take the digit 5 and the sum will be 19(7+7+5) which is a prime  

           number.

Hence the number is 775.

37 = ending with 7

unit's digit in the cube..3

56 = ending with 6

unit's digit in the cube..2

133 = ending with

unit's digit in the cube..7

hope it : ( : )