$flags = int rand( 2**64 );;

print for grep $flags & 1 << $_, 0 .. 63;;
49
50
51
54
55
57
58
59

printf "%u\n", $flags;;
1066790161733386240

$t = 0; print $t += 1<<$_ for  grep $flags & 1 << $_, 0 .. 63;;
562949953421312
1688849860263936
3940649673949184
21955048183431168
57983845202395136
202099033278251008
490329409429962752
1066790161733386240