I divisori di 19912990 sono 16, elencati qui di seguito: 1; 2; 5; 10; 103; 206; 515; 1030; 19333; 38666; 96665; 193330; 1991299; 3982598; 9956495; 19912990
19912971, 19912972, 19912973, 19912974, 19912975, 19912976, 19912977, 19912978, 19912979, 19912980, 19912981, 19912982, 19912983, 19912984, 19912985, 19912986, 19912987, 19912988, 19912989, 19912991, 19912992, 19912993, 19912994, 19912995, 19912996, 19912997, 19912998, 19912999, 19913000, 19913001, 19913002, 19913003, 19913004, 19913005, 19913006, 19913007, 19913008, 19913009