Tuesday, August 4, 2009

638

638 = 2 x 11 x 29.

638 is the sum of four consecutive primes: 151 + 157 + 163 + 167 = 638.

638 is the solution to the postage stamp problem for 7 denominations and 6 stamps.


638 is a centered heptagonal number.


The Islamic calendar was introduced in the year 638.

Source: Wikipedia
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