By the condition of the problem, we have a2∣(a3+b3+c3), b2∣(a3+b3+c3) and c2∣(a3+b3+c3). Since a, b and c are coprime, we see that a2b2c2∣(a3+b3+c3).
Without loss of generality, suppose that a≥b≥c, so
3a3≥a3+b3+c3≥a2b2c2⇒a≥3b2c2,
and
2b3≥b3+c3≥a2⇒2b3≥9b4c4⇒b≤c418.
We see that if c≥2⇒b≤1, the result contradicts b≥c. Thus, c=1.
If c=1 and b=1, then a=1, so (a,b,c)=(1,1,1) is a solution.
If c=1, b≥2 and a=b, then b2∣b3+1, which is a contradiction!
If b≥2 and a>b>c=1, then
a2b2∣(a3+b3+1)⇒2a3≥a3+b3+1≥a2b2⇒a≥2b2,
and by c=1,
a2∣(b3+1)⇒b3+1≥a2≥4b4⇒4b3+4≥b4.