What will be the least common multiple

$ 15 = 3 \times 5 $

$ 35 = 5 \times 7 $

$ 42 = 2 \times 3 \times 7 $

$ 72 = 2^3 \times 3^2 $

$ \text{LCM} = 2^3 \times 3^2 \times 5 \times 7 $

$ = 8 \times 9 \times 5 \times 7 $

Answer = 2520