Find Samantha's Phone Number

You are new to a high school. You have one new friend, Samantha. You asked her cell phone number, which is a ten digit number. But she denied to give it to you directly. She gave you a riddle to find her phone number. She told you that the last ten digits of the number X is her phone number, where X is ${2014}^{2015} + {2015}^{2014}$ .

Find which digit is at most repeated in her phone number.

Edit : Her phone number isn't $9876543210$ - in which all digits are repeated only once.