We have so much faith in RSA we give you not just the product of the primes, but their sum as well!
Run the solution script.py, which uses the equations for p and p-q from this paper (Archive).
The two equations can be combined to form: p=(x+sqrt(x^2-4*n))/2.
gmpy2 is used to store large numbers and it's precision is set to 2048 ate the beginning of the script to ensure that no digits are lost.
picoCTF{3921def5}