596

596 = 2² x 149.

596 has a representation as a sum of two squares: 596 = 14² + 20².

596 is the maximum number of regions into which 34 lines divide the plane.

596 is the number of Hamiltonian cycles of a 4 x 9 rectangle graph.

596 was the code name for China's first nuclear weapons test, detonated Oct. 16, 1964.

Source: What's Special About This Number?

961

961 = 31². It is a perfect square.

961 is the largest square with strictly decreasing digits. It is also the largest prime power of a prime with strictly decreasing digits.

The digits of 961 can be rearranged to give two other squares: 169 = 13² and 196 = 14².

961 is 12321 in base 5 and 4241 in base 6.

961 beer is brewed in Beirut, Lebanon.

Source: Number Gossip

705

705 = 3 x 5 x 47.

705 is the smallest Lucas psuedoprime.

705 is a rhombic matchstick number: n(3n + 2) for n = 15.

705 is an odd interprime because it lies at the midpoint between two consecutive odd primes, 701 and 709.

The IBM 705 was one of the most powerful data processing systems available in the mid-1950s.

Source: On-Line Encyclopedia of Integer Sequences

208

208 = 2⁴ x 13.

208 has a representation as a sum of two squares: 208 = 8² + 12².

208 = 2⁸ - 48.

208 is a divisor of 25² - 1.

208 = 2² + 3² + 5² + 7² + 11².

208 is the telephone area code for the state of Idaho.

Source: Prime Curios!

3892

3892 = 2² x 7 x 139.

3892 has the representation 2⁴ x 3⁵ + 4.

3892 is a divisor of 43⁶ - 1.

3892 is 30004 in base 6 and 7464 in base 8.

The 3892nd triangular number contains only the digits 5, 7, and 8: 7575778.

The asteroid 3892 Dezsö was discovered in 1941.

Source: On-Line Encyclopedia of Integer Sequences

863

863 is a prime number.

863 is the largest three-digit prime that can be written as the sum of fifteen consecutive primes: 29 + 31 + 37 + 41 + 43 + 47 + 53 + 59 + 61 + 67 + 71 + 73 + 79 + 83 + 89 = 863.

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

863 = (11 + 71) + (11 x 71), where 11, 71, and 863 are all primes.

863 is a value of n so that n(n + 6) is a palindrome: 863(869) = 749947.

863 is a telephone area code for central Florida.

Source: Prime Curios!

372

372 = 2² x 3 x 31.

372 has a unique representation as a sum of three squares: 372 = 4² + 10² + 16².

372 is a hexagonal pyramidal number, having the form n(n + 1)(4n - 1)/6 for n = 8.

372/(3 + 7 + 2) is a prime number, 31.

101,556 = 273 x 372 = 651 x 156.

NGC 372 is a triple star in the constellation Pisces.

Source: Prime Curios!

446

446 = 2 x 223.

446 is the smallest number that can be written as the sum of three distinct squares in eight different ways: 446 = 21² + 2² + 1² = 19² + 9² + 2² = 19² + 7² + 6² = 18² + 11² + 1² = 17² + 11² + 6² = 15² + 14² + 5² = 15² + 11² + 10² = 14² + 13² + 9².

446 is 676 in base 8 and 545 in base 9.

446 is a self number. A self number is an integer that cannot be generated by any other integer added to that other integer's digits.

446 Aeternitas is an asteroid discovered in 1899.

Source: What's Special About This Number?

655

655 = 5 x 131.

655 is a semiprime (product of two prime numbers) that is the product of two Sophie Germain primes, 5 and 131.

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

655 is a divisor of 61⁵ - 1.

655 is 22033 in base 4 and 10110 in base 5.

Iran Air Flight 655 was an airliner shot down by U.S. missiles in 1988 toward the end of the Iran-Iraq war.

Source: On-Line Encyclopedia of Integer Sequences

223

223 is a prime number.

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

223 is the smallest prime with three prime digits. The sum of the digits of first primes up to 223 is 449.

223 is the smallest prime whose reversal has more than two prime divisors: 322 = 2 x 7 x 23.

223 is the final chapter of Mark Haddon's novel The Curious Incident of the Dog in the Night-Time, which uses just prime numbers for its chapters.

Source: Number Gossip

642

642 = 2 x 3 x 107.

642 is a sphenic number because it the product of three distinct primes.

642 is the smallest number with the property that its first six multiples contain the digit 2: 642, 1284, 1926, 2568, 3210, 3852.

642 is 22002 in base 4, 1202 in base 8, and 456 in base 12.

642 Clara is an asteroid orbiting the Sun.

Source: What's Special About This Number?

426

426 = 2 x 3 x 71.

As the product of three distinct primes, 426 is known as a sphenic number.

426 is a stella octangula number. The stella octangula is a stellation of the octahedron.

426 is a number such that 10⁴²⁶ + 3 is a prime.

426 is a multiple of 6 that contains 6 in its decimal representation.

In the 1979 movie Alien, the spaceship Nostromo goes to the desolate planetoid LV-426.

Source: What's Special About This Number?

808

808 = 2³ x 101.

808 has a representation as a sum of two squares: 808 = 18² + 22².

The first 808 digits of 808! form a prime number.

808 is a strobogrammatic number. It is the same number when rotated 180 degrees on an axis perpendicular to the plane on which the number is written.

The 808th Fibonacci number plus and minus 808 results in (13²)-digit primes.

The Roland TR-808 was one of the first programmable drum machines, introduced in early 1980.

Source: Prime Curios!

314

314 = 2 x 157.

314 has a representation as a sum of two squares: 314 = 5² + 17².

314 is the smallest number that can be written as the sum of three positive squares in six ways: 314 = 17² + 4² + 3² = 16² + 7² + 3² = 15² + 8² + 5² = 13² + 9² + 8² = 13² + 12² + 1² = 13² + 9² + 8².

314 is 222 in base 12.

314 is the only number that together with its sixth power, 958468597212736, has each digit from 1 to 9 occurring exactly twice.

314 is the telephone area code for St. Louis, Missouri.

Source: Number Gossip

2265

2265 = 3 x 5 x 151. It has exactly three distinct palindromic prime factors.

The sum of the digits of 2265 equals the sum of the digits of its prime factors: 2 + 2 + 6 + 5 = 3 + 5 + 1 + 5 + 1 = 15.

The product of the digits of 2265 is eight times the sum of the digits: 2 x 2 x 6 x 5 = 8(2 + 2 + 6 + 5) = 120.

2265 is 14253 in base 6. It uses each positive digit just once.

2265 is a year in which January 1 falls on a Sunday.

Source: On-Line Encyclopedia of Integer Sequences.

3531

3531 = 3 x 11 x 107.

3531 is a composite number whose three prime factors are distinct in length.

3531 is 24203 in base 6 and 13203 in base 7.

3531 is a multiple of 11 having only odd digits.

3531 is the number of sums payable using exactly 39 banknotes of denominations 1, 5, 10, 20, 50, and 100. For n = 1, there are precisely six payable sums.

The Lego 3531 set was a kit for building the Znap Tri-bike.

Source: On-Line Encyclopedia of Integer Sequences

9002

9002 = 2 x 7 x 643.

9002 = 3² x 10³ + 2.

9002 is a value of n such that n + 7 and n(n + 7) are palindromes: 9009 and 81099018.

9002 is a number n such that n(n + 7) is a palindrome: 9002(9009) = 81099018.

ISO 9002 was an international standard to used to certify manufacturing quality.

Source: What's Special About This Number?