Firework, 6.3 million
E.T., 5.6 million
California Gurls, 5.5 million
Hot N Cold, 5.4 million
Teenage Dream, 4.5 million
I Kissed A Girl, 4.4 million
Roar, 4.0 million
These singles alone are enough to put her on the top 10 best-selling digital track artists of all-time list
