Numbers 1210-1229

A page of the Numeropedia - the Special Encyclopedia of Numbers

All Numbers & [1K…) * [2K…) * [3K…) * [4K…) * [5K…) * [6K…) * [7K…) * [8K…) *  [9K…)  & [10K] & [100K]

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1,210

[Math.]  The first pair of amicable numbers greater than 1000 is (1184, 1210).

1,211 & 1,214

[History]  Genghis Khan invaded China in 1211 and captured Peking in 1214

1213, 1217, 1223 & 1229

[Math.]  A sequence of consecutive reversible prime numbers:  1193, 1201, 1213, 1217, 1223, 1229, 1231, 1237, 1249 and 1259.

1,212

[Sport]  The maximum number of dimple was made on a golf ball is 1212.

The number of dimples on a golf ball usually are: 252, 286, 332, 336, 360, 384, 392, 410, 416, 420, 422, 432, 440, 480, 492 or 500. (References [6] )

1,221

[Math.]

 33×34 = 1122 33×35 = 1155 33×36 = 1188 33×37 = 1221 33×47 = 1551 33×57 = 1881

 333×334 = 111,222 333×335 = 111,555 333×336 = 111,888 333×337 = 112,221 333×347 = 115,551 333×357 = 118,881

… (generalizable pattern) …

1,223

[Math.]  The 200th prime number.

1,225

[Math.]  A triangular number (sum of all integers from 1 to 49):  1225 = 1+2+…+48+49.

[Math.]  The 3rd square number (352) that is also a triangular number. The nth root number is 6 times the (n–1)th root minus the (n–2)th root: 1, 62, 352, 2042, 11892

[Math.]  Repeatedly inserting numbers 12 between the digits 1 and 2 in the square number 1225 = 352 yields other squares 112225 = 3352, 11122225 = 33352, 1111222225 = 333352

1,228

[Math.]  A base system of multigrade equalities:

1+6+7+17+18+23 = 72 = 2+3+11+13+21+22

12+62+72+172+182+232 = 1,228 = 22+32+112+132+212+222

13+63+73+173+183+233 = 23,472 = 23+33+113+133+213+223

14+64+74+174+184+234 = 472,036 = 24+34+114+134+214+224

15+65+75+175+185+235 = 9,770,352= 25+35+115+135+215+225. (References [??])

Multigrade equalitiesstill hold by adding any integer n to every base term in both sides.  Hence, the base equality always has number 1 appearing in one side.

1,229

[Math.]  The number of prime numbers less than 10,000.

1,210-1229

1,230-1249

1,250-1279

1,280-1299