Sanity check for Carmichael numbers

Question

I made a simple calculation in Sagemath (see [1]) to check results of Table in 2, for producing a Carmichael number with three prime factors. I used the parameters of the previous table, and as far as I understood, I have to take a Carmichael number of the form $P\cdot Q\cdot R,$ and $P,Q,R,$ are prime numbers.

T = product(Primes()[1:15])
A,C,X = 35, 135449, 83421
#A,C,X = 41,141847,803985
def dubner_parameters(T,A,C,X):

    M = ((T*C-1)^A)/4
    P = 6*M + 1
    Q = 12*M + 1
    R = 1 + (P*Q-1)/X
    N = P*Q*R
    return N,P,Q,R,M
N,P,Q,R,M = dubner_parameters(T,A,C,X)

Checking is_prime(P) I got false. I expected to get true. What I made wrong?