How long in meter is a typical radio wave which has a frequency of 560 kilohertz?

Well, consider that a wave's wavelength is equivalent to its velocity multiplied divided by its frequency. If we make the fairly safe assumption that it travels at 3 x 10^8 meters per second (the speed of electromagnetic radiation in a vacuum), we can calculate its wavelength as

(3 x 10^8)/560000

or

535.7 meters