9.461…×1012

[Astronomy]  The approximate distance (km, kilometers) that light travels in vacuum in a year. It is called a light year.

9,746,347,772,161

[Math.]  The first Carmichael number consisting of 9 prime factors: 9,746,347,772,161 = 7×11×13×17×19×31×37×41×641.

1,099,999,999,989 & 3,299,999,999,967 & 9,899,999,999,901

[Math.]

(*)   332×9 = 1089×9 = 9,801 = 992 & 1089×9801 = 10,673,289 = 32672

1089…1089×9 = 9801…9801  & 1089…1089×9801…9801  = 3267…32672

(**)  10989×9 = 98901 & 10989×98901 = 1,086,823,089 = 329672

10989…10989×9 = 98901…98901 & 10989…10989×98901...98901 = 32967…329672

...

(***)   1,099,999,999,989×9 = 9,899,999,999,901 &

1,099,999,999,989×9,899,999,999,901 = 3,299,999,999,9672

1099999999989…109999999989×9 = 9899999999901…9899999999901 &

1099999999989…1099999999989×9899999999901...9899999999901 =

= 32999999967…32999999999672

...

(****)  109…989×9 = 989…901 & 109...989×989…901 = 329…9672

109…989...109…989×9 = 989…901...989…901  &

109…989…109…989×989…901...989…901 = 329…967…329…9672.

9,876,543,209,877

[Math.]

9×9+(9–2) = 88

98×9+(9–3) = 888

987×9+(9–4) = 8,888

9,876×9+(9–5) = 88,888

98,765×9+(9–6) = 888,888

987,654×9+(9–7) = 8,888,888

9,876,543×9+(9–8) = 88,888,888

98,765,432×9+(9–9) = 888,888,888

987,654,321×9+(9–10) = 8,888,888,888

9,876,543,210×9+(9–11) = 88,888,888,888

98,765,432,099×9+(9–12) = 888,888,888,888  = 98,765,432,100×9–12.

987,654,320,988×9+(9–13) = 8,888,888,888,888

9,876,543,209,877×9+(9–14) = 88,888,888,888,888

98,765,432,098,766×9+(9–15) = 888,888,888,888,888

987,654,320,987,655×9+(9–16) = 8,888,888,888,888,888

9,876,543,209,876,544×9+(9–17) = 88,888,888,888,888,888

...

9,876,543,210,987

[Math.]

1×8+1 = 9

12×8+2 = 98

123×8+3 = 987

1234×8+4 = 9876

12,345×8+5 = 98,765

123,456×8+6 = 987,654

1,234,567×8+7 = 9,876,543

12,345,678×8+8 = 98,765,432

123,456,789×8+9 = 987,654,321

1,234,567,890×8+90 = 9,876,543,210

(Start of new cycle)

12,345,678,901×8+901 = 98,765,432,109

123,456,789,012×8+9002 = 987,654,321,098

1,234,567,890,123×8+90,003 = 9,876,543,210,987

12,345,678,901,234×8+900,004 = 98,765,432,109,876

123,456,789,012,345×8+9,000,005 = 987,654,321,098,765

1,234,567,890,123,456×8+90,000,006 = 9,876,543,210,987,654

12,345,678,901,234,567×8+900,000,007 = 98,765,432,109,876,543

123,456,789,012,345,678×8+9,000,000,008 = 987,654,321,098,765,432

1,234,567,890,123,456,789×8+90,000,000,009 = 9,876,543,210,987,654,321

12,345,678,901,234,567,890×8+ 900,000,000,090 = 98,765,432,109,876,543,210

(end of cycle)  ...

9,988,776,677,889

[Math.]

99,889×11+(11–1) = 1,098,789

998,877,889×11+(11–1) = 10,987,656,789

9,988,776,677,889×11+(11–1) = 109,876,543,456,789

99,887,766,556,677,889×11+(11–1) = 1,098,765,432,123,456,789

9,999,999,999,971

[Math.]  The largest 13-digit prime number,

1013–29 = 9,999,999,999,971.

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