Special two digit number

A special two-digit number is a number such that when the sum of the digits of the number is added to the product of its digits, the result is equal to the original two-digit number. 

Examples : 

input : 59.
output : 59 is a Special Two-Digit Number
Explanation:
Sum of digits = 5 + 9 = 14
Product of its digits = 5 x 9 = 45
Sum of the sum of digits 
and product of digits = 14 + 45 = 59

input: 29
output: 29 is a Special Two-digit Number
Explanation:
Sum of digits = 9 + 2 = 11
Product of digits = 9 * 2 = 18
Sum of the sum of digits 
and product of digits = 11 + 18 = 29

Approach: 

Extract the first and last digit of the number and add and multiply the digits separately. Then, add the sum and product of the digits of the two-digit number and compare it to the original number. If they are same, then it is a Special Two-Digit Number, else it is not.

Below is the implementation of above approach: 

59 is a Special Two-Digit Number

Time Complexity: O(1), As we are performing constant time operations.
Auxiliary Space: O(1), As constant extra space is used.