1.52415788 × 1016
123456789 x 16 = 1975308624
45 x 123456789 = 5555555505
2 x 123456789 = 246913578
289526540575185
370370367
1,524,157,763,907,942
1.21932631 × 1018
123456789 + 123456789 = 246913578
100000 times 10000000000000 is 1,000,000,000,000,000,000
100000 times 123456789123456789 is 12,345,678,912,345,678,400,000
123456789 can be written in 362,880 different ways, you can calculate this by using the permutation function nPr.