19 can be expressed as the sum of four perfect cubes:
19 = 333 + (-29)3 + (-25)3 + 163
So can 6941:
6941 = (-3476)3 + 30903 + 23173 + 3843
Can every integer be expressed in this way? It’s conjectured that the answer is yes, but no one has yet managed to prove it.