12,837,064

12,837,064 = 2³ x 631 x 2543 (via WolframAlpha)

12,837,064 is the number of decimal digits in the 47th known Mersenne prime, discovered April 12, 2009.

This prime is at present the second largest known prime number, a mere 141,125 digits smaller than the record-breaking Mersenne prime found last August.

Source: Great Internet Mersenne Prime Search