6. Among the seven-digit numbers formed by the digits $0,1,2,3,4,5,6$, the number of permutations that do not contain "246" and "15" is ( ).
(A) 3606
(B) 3624
(C) 3642
(D) 4362
6.C.

Since the total number of permutations of the 7 digits $0,1, \cdots, 6$ into a seven-digit number with the first digit not being zero is $\mathrm{A}_{7}^{7}-\mathrm{A}_{6}^{6}=4320$, but among these, the number where “246” are together is $\mathrm{A}_{4}^{4} \mathrm{C}_{4}^{1}=96$, and the number where “15” are together is $\mathrm{A}_{5}^{5} \mathrm{C}_{5}^{1}=600$, and the number where both “246” and “15” are together is $A_{3}^{3} C_{3}^{1}=18$. Therefore, the number of permutations that do not contain “246” and “15” is $4320-96-600+18=3642$ (cases).