If you have the numbers file on your iCloud Drive or stored in numbers that is using iCloud you just goto iCloud.com > Numbers > right click the file > select download > chose excel (or if you can't open excel on the galaxy you can also convert to a PDF which I'm sure the galaxy can natively open). Apple will convert it for you and it will download.
Never tired it but you might be able to do that right from the Galaxy phone.
Good luck.