But students at Britain's University of Leicester say the real number would be close to two and a half million birds.
In a tongue-in-cheek study in the Journal of Physics Special Topics, four students calculated the force lift required to pick up a peach of 1.025 tonnes and a radius of six metres (19.5 feet).
"Although James could have successfully sailed his peach in the manner described by Roald Dahl, for a peach of the dimensions calculated, it would not be possible to fly such a heavy object with the assistance of such a diminutive number of birds," says their "paper."
"He would have to harness 2,425,907 seagulls in order to fly to America."
The authors add a touch of scientific caution, though.
"Whether the Silkworm and Mrs. Spider could have managed this is unknown," they say, referring to the two companions who lure the gulls into lifting the peach.