from bisect import bisect

def PrimeList(N):
    P = [1] * (N + 1)
    P[0] = P[1] = 0
    for i in range(2, N + 1):
        if P[i]:
            for j in range(i + i, N + 1, i):
                P[j] = 0
    PL = []
    for i in range(N + 1):
        if P[i] == 1:
            PL.append(i)
    return PL

A = [-1]
PL = PrimeList(10**7)
PLN = len(PL)
for i in range(1, PLN):
    if PL[i] - PL[i-1] == 2:
        mp = PL[i] * PL[i-1]
        if mp > 10 ** 14:
            break
        A.append(mp)

for _ in range(int(input())):
    N = int(input())
    print(A[bisect(A,N) - 1])