Let the three parts of the number 207 are
a1 = a - d
a2 = a
a3 = a + d
Clearly a1, a2 and a3 are in AP with common difference as d.
Now, by given condition,
Sum = 207
a1 + a2 + a3 = 207
(a - d) + a + (a + d) = 207
3a = 207
a = 69
Also,
a1a2 = 4623
(a - d)a = 4623
(69 - d)69 = 4623
69 - d = 67
d = 69 - 67
d = 2
Hence, required three parts are 67, 69, 71.