We present results of a variability search in the intermediate-age open cluster NGC 6866 from 29 nights over two observing seasons .
We find 28 periodic variables , of which 19 are newly identified .
The periods of these variables , which have V magnitudes from 11.5 to 19.3 mag , range from \sim 48 min to 37 d. We detected several \delta -Scuti stars , some of which are of high amplitude , as well as \gamma -Doradus , rotational variables and eclipsing binaries .
In order to study the physical properties of the cluster , we obtained UBVRI photometry of all the stars on a good photometric night .
The radial distribution of the stellar surface density shows that the cluster has a radial extent of about 7 arcmin ( \sim 3 pc ) with a peak density of 5.7 \pm 0.7 stars/arcmin ^ { 2 } at the cluster center .
The colour-colour diagram indicates a reddening of E ( B - V ) = 0.10 mag towards NGC 6866 .
A distance of \sim 1.47 kpc and an age of \sim 630 Myr is estimated from the colour-magnitude diagram using the theoretical isochrones of solar metallicity .