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Term

Flippable

Every digit has a 180° rotational counterpart (0, 1, 8 self-rotate; 6 and 9 swap). A strict superset of strobogrammatic — flippable numbers may rotate to a different number, like 16 ↔ 91.

539 numbers tagged.

A flippable number consists entirely of digits that have a clean rotational counterpart when the number is rotated 180°. The digits 0, 1, and 8 rotate to themselves; 6 and 9 rotate to each other; the rest (2, 3, 4, 5, 7) have no clean rotation.

Flipping is an involution: flip(flip(n)) = n. When the rotated value equals the original, the number is strobogrammatic (e.g., 88, 1881, 96 with 6/9 viewed in mirror).

When the rotated value differs, you get pairs: 16 ↔ 91, 19 ↔ 61, 109 ↔ 601, 198 ↔ 861. The most well-known flippable amusements come from calculator culture — 5318008 rotates to BOOBIES in seven-segment display, and 0.7734 reads hELLO upside down.

1 6 8 9 10 11 16 18 19 60 61 66 68 69 80 81 86 88 89 90 91 96 98 99 100 101 106 108 109 110 111 116 118 119 160 161 166 168 169 180 181 186 188 189 190 191 196 198 199 600 601 606 608 609 610 611 616 618 619 660 661 666 668 669 680 681 686 688 689 690 691 696 698 699 800 801 806 808 809 810 811 816 818 819 860 861 866 868 869 880 881 886 888 889 890 891 896 898 899 900 901 906 908 909 910 911 916 918 919 960 961 966 968 969 980 981 986 988 989 990 991 996 998 999 1,000 1,001 1,006 1,008 1,009 1,010 1,011 1,016 1,018 1,019 1,060 1,061 1,066 1,068 1,069 1,080 1,081 1,086 1,088 1,089 1,090 1,091 1,096 1,098 1,099 1,100 1,101 1,106 1,108 1,109 1,110 1,111 1,116 1,118 1,119 1,160 1,161 1,166 1,168 1,169 1,180 1,181 1,186 1,188 1,189 1,190 1,191 1,196 1,198 1,199 1,600 1,601 1,606 1,608 1,609 1,610 1,611 1,616 1,618 1,619 1,660 1,661 1,666 1,668 1,669 1,680 1,681 1,686 1,688 1,689 1,690 1,691 1,696 1,698 1,699 1,800