It depends on which way you're going.
Equatorial: 40,075.02 km = 24901.46 mi
Along a meridian: 40,007.86 km = 24859.73 mi
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In either case, this is probably the dimension of the reference model that geographers use for the Earth. The actual circumference would be terribly difficult to measure with this sort of accuracy, even if you could define what you meant by it.
Equatorial: 40,075.02 km = 24901.46 mi
Along a meridian: 40,007.86 km = 24859.73 mi
_____
In either case, this is probably the dimension of the reference model that geographers use for the Earth. The actual circumference would be terribly difficult to measure with this sort of accuracy, even if you could define what you meant by it.