A memory device includes a memory cell array, a plurality of bit lines, and a plurality of page buffers including a plurality of cache latches, exchanging data with the memory cell array through the plurality of bit lines, wherein the plurality of cache latches are arranged in a column direction in parallel with the plurality of bit lines and a row direction perpendicular to the plurality of bit lines, and have a two-dimensional arrangement of M stages in the column direction, where M is a positive integer not corresponding to 2L and L is zero or a natural number.