491

[Math.]  A prime number whose digits are distinct and in the English alphabetical consecutive order: four nine one.

 

492

[Math.]  144,648 = 861×168 = 492×294.

 

[Sport]   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])

 

[World]  The ISO-3166 country code for Monaco.

 

493

[Math.]  The first Lychrel number in the series produced by repeatedly applying the 196-algorithm (reversal-addition algorithm) to the number 196 and some other Lychrel numbers is: 887 = 196+691 = 295+592 = 394+493 = 790+097.

 

494

[Math.]  88+209 = 297 and 88,209 = 2972 and 494+209 = 703 and 494,209 = 7032 and 297+703 = 1000.

 

495

[Math.]   (Sequence of numbers 49…9…95, with an odd number of digits 9)

4952 = 245025 = (2–4+502–5)2.

 

[Math.]   495+459 = 954, using 3 permutations of 459.

 

[Math.]  0495×12 = 5,940.

 

496

[Math.] A triangular number (sum of all integers from 1 to 31): 496 = 1+2+…+30+31.

 

[Math.]  The 3rd perfect number; i.e., a number equal to the sum of all of its proper divisors, including 1 (or also called aliquot divisors). The first perfect numbers are: 6, 28, 496, 8128, 212(213–1) = 33550336, 216(217–1) = 8,589,869,056 and 218(219–1) = 137,438,691,328…

 

[World]  The ISO-3166 country code for Mongolia. 

 

497 & 499

[Math.] 

94 = 47×2 and, reversely, 49 = 47+2

994 = 497×2 and, reversely, 499 = 497+2

9994 = 4997×2 and, reversely, 4999 = 4997+2

99994 = 49997×2 and, reversely, 49999 = 49997+2

...

999,999,999,994 = 499,999,999,997×2 and, reversely,

499,999,999,999 = 499,999,999,997+2 …

 

498

[World]   The ISO-3166 country code for Moldova.

 

499

[Astro.]   The average time interval for the sunlight from the Sun to reach the Earth, 8 minutes 19 seconds = 499 seconds.

 

[Math.]   A prime number.

 

[Math.]   Its odd powers end with 499. Its even powers end with 001. 

 

499 & 497 (See more above)

 

490-499

[Library]  Numbers 400-499 are the first 3 digits in Dewey Decimal Classification System call numbers for library books in Languages and Linguistics. Numbers 490-499 are for books in less popular Languages such as Celtic, Asian, African and American native…

 

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References [6]: Scientific American, I. Stewart, Mathematical Recreations, February 1997.