45 x 123456789 = 5555555505
45 and 45/5 = 9
100000 x 123456789 = 12345678900000
123456789 x 16 = 1975308624
2 x 123456789 = 246913578
1.52415788 × 1016
289526540575185
370370367
1,524,157,763,907,942
1.21932631 × 1018
123456789 + 123456789 = 246913578
Well, honey, the sum of 123456789 is 45. But let me tell you, that number is so big I'd need a calculator and a cup of coffee to double-check it. So, take my word for it or grab a calculator and do the math yourself.
123456789 can be written in 362,880 different ways, you can calculate this by using the permutation function nPr.