How big a number can it factor reliably using Shor's algorithm?
According to [1], that record still stands at only 21. All larger numbers you've heard of being factored suffered from one or more of:
1) factoring numbers of a special form (n+i)*(n-i) for very small i
2) using an algorithm with prior knowledge of the predetermined factors
3) using adiabatic computing/quantum annealing rather than Shor's algorithm
Shor's algorithm (or its adaptation to elliptic curve discrete log) is the only one threatening widely used cryptographic primitives, once we have a few thousand logical qubits to work with, which due to the necessary quantum error correction translates to millions of raw qubits.
> An Eagle quantum computer can deal with system models in 2127 states simultaneously.
Obvious typo in there; they mean 2^{127} states.
[1] https://en.wikipedia.org/wiki/Integer_factorization_records#...