Sirius XM has hit the 20 million subscriber mark, and it's calling on a member of The Beatles to commemorate it.

Starting tonight at 5 p.m. PT, several Sirius XM channels, including Paul McCartney's Band On the Run Radio, Howard 101, and Classic Vinyl, will air Paul McCartney's concert live from the Apollo Theater. The concert, which was first announced last month, is accessible at no additional charge for current Sirius or XM subscribers.

It has been a good week for Sirius XM. Last Thursday, the company announced that it had re-signed Howard Stern to another five-year contract. The radio personality, who is finishing a five-year deal with Sirius estimated at $500 million, kept listeners on the edge of their seats for months about his plans after 2010. He indicated at times throughout the year that he would either retire or try something new. There was even a rumor swirling around that he was close to inking a deal with Apple to offer his show through iTunes and other Apple-owned platforms.

Stern has also been quite outspoken on his show about his contribution to that 20 million subscribers figure, saying that he played an integral role in helping Sirius XM reach that figure.

From a financial perspective, Sirius XM has been enjoying a year that some thought impossible a couple years ago.

The company announced back in October that it enjoyed a profit of more than $67 million during the third quarter. That followed similarly impressive profits in the first and second quarters, totaling nearly $57 million. It expects to generate $2.8 billion in total revenue this year.

That success stands in stark contrast to the company's past performance. In 2008, the satellite radio provider posted a loss of $5.3 billion on $1.65 billion in revenue. Last year, it lost nearly $529 million on $2.39 billion in revenue.