How to trim the alphabets along with leading zeroes from a std::string

I have a std::string variable with value as ABC000090007012.
I want to trim the alphabets and the leading zeroes prepending the actual number 90007012 into an unsigned int. What is the best way to do that using C++11?

Code:

std::string str = ABC000090007012;
unsigned int number = // How to get the 90007012 out of it?