Well, it is very easy to calculate.
Since the CIC (Circuit Identification Code) is 14 bits, a single SS7 trunk can theoretically support up to 16,384 channels / “calls”.
BUT!!! Each SS7 trunk capacity is limited to either 56Kbps or 64Kbps (the most used).
And one SS7 trunk at practice can handle no more than 20 calls per second (20 simult calls).
And it is very recommended to have the SS7 links in pair for redundancy. So – 2 SS7 links.