What's the next number and why?
The next number is:
1,602,817,493,294,903 because the original 'sequence' is just one number (1,602,817,493,294,902)
With one positive integer and no additional information, the next number could be interpreted as the last plus one as in the sequence 1,2,3,4,..., n. For example, ask a person what the next number after 3 is and most people will guess 4 in the absence of any other information.
The next number is 1,602,817,493,294,903 since the comma ',' is,in many countries, accepted as a thousands separator. If you meant 1,602,817,493,294,902 as a sequence, you may want to specify 'the next number in this sequence', although it seems as though you meant it as a joke/trick question.