Other contributors have said "How long is the line around the Equator?" is the same question as "How long in miles is the equator?" If you believe that these are not asking the same thing and should be answered differently, click here
Ignoring mountains, and assuming the Earth is perfectly spherical, the equator's length is equal to the circumference of the Earth, or approximately 24,000 miles. As far as being "long", no other...