1137

1137 = 3 x 379.

1137 is the product of two primes, as are 1136 (2⁴ x 71) and 1138 (2 x 569).

1137 is a semiprime (product of two distinct primes), as are 1139 (17 x 67) and 1141 (7 x 163).

1137 is the maximum value of n so that there exist seven denominations of stamps so that every postage from 1 to n can be paid for with at most seven stamps (postage stamp problem). It is also the solution to the postage stamp problem for n denominations and seven stamps, for n = 7.

1137 in base 2 (binary) is palindromic: 10001110001.

1137 is 696 in base 13 and 393 in base 18.

Atlantic Records 1957 release 45-1137 featured "Rakin and Scrapin" by Dean Beard and the Crew Cats.

Source: What's Special About This Number?

72

72 = 2³ x 3².

72 is the sum of the first eight even numbers: 72 = 2 + 4 + 6 + 8 + 10 + 12 + 14 + 16.

72 is the sum of nine consecutive integers: 72 = 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12.

72 has a representation as a sum of two squares: 72 = 6² + 6².

72 is 2200 in base 3, 200 in base 6, 110 in base 8, 66 in base 11, 44 in base 17, 33 in base 23, and 22 in base 35.

The normal human pulse rate is about 72 beats per second at rest.

The Cambodian alphabet, with 72 letters, is the longest in the world.

Source: Phillips, R. 2004. Numbers: Facts, Figures and Fiction. Badsey Publications.

469

469 = 7 x 67.

469 is a heptagonal number. 469 is also a centered hexagonal number.

469 is a value of n for which n! - 1 is a prime number.

469 is the sum of three distinct positive cubes: 469 = 7³ + 5³ + 1³.

Inserting a zero between adjacent digits makes 469 a prime number: 40609.

469 Argentina is a main-belt asteroid discovered in 1901.

Source: What's Special About This Number?

663

663 = 3 x 13 x 17.

663 is a number that cannot be written as a sum of three squares.

663 has the representation 663 = 3⁶ - 66.

663 is the generalized Catalan number C(15,3).

663 is the numerical equivalent of ONE on a touch-tone telephone.

Source: Number Gossip

144

144 = 2⁴ x 3².

144² = 12², a perfect square. If you reverse the digits, 21² = 441.

144 has a unique representation as a sum of three squares: 144 = 4² + 8² + 8².

144 is a square number. Divide it by 4 and you get 36, which is also square. Does this happen with any other square numbers?

144 is the 12th Fibonacci number.

144 is 99 in base 15.

The interior angles in a regular decagon measure 144 degrees. In counting objects, 144 is called a gross (a dozen dozens).

Source: WolframAlpha

843

843 = 3 x 281.

843 is the 14th Lucas number.

843 is a divisor of 53⁴ - 1.

843 is 31023 in base 4, 11333 in base 5, 3523 in base 6, 2313 in base 7, and 1513 in base 8, all ending in 3. 843 is 443 in base 14, 223 in base 20, and 123 in base 28.

843 is palindromic in base 2: 1101001011.

Telephone area code 843 covers coastal South Carolina, including Charleston, Myrtle Beach, and Hilton Head Island.

Source: WolframAlpha

700

700 = 2² x 5² x 7.

700 is the sum of four consecutive primes: 700 = 167 + 173 + 179 + 181.

700 is a number that cannot be written as a sum of three squares.

700 is 221221 in base 3 and 2020 in base 7.

700 is the number of n-bead necklaces with four colors, for n = 7.

The first known recorded use of the zero in Europe occurred in the year 700.

Source: Wikipedia