633

633 = 3 x 211.

633 is 1001111001 in base 2 (binary). It is 333 in base 14.

633 has the representation 633 = 3⁶ - 96.

633 is a divisor of 55⁵ - 1.

633 is the smallest number n whose fifth root has a decimal part that begins with the digits of n: 3.633128. . .

633³ = 253,636,137 = (2 - 5 + 3 + 636 + 1 + 3 - 7)³.

633 Squadron was a 1964 British film that depicted the exploits of a fictional World War II fighter-bomber squadron.

Source: What's Special About This Number?

327

327 = 3 x 109. The digits of 327 are themselves all primes.

327 is largest number n such that n, 2n, and 3n contain every digit from 1 to 9 exactly once: 327, 654, 981. In other words, the sum 327 + 654 = 981 contains each of the digits from 1 to 9 once.

327 is the number of 5s among the digits of all four-digit primes.

327 is a divisor of 76⁴ - 1.

327 is a number that cannot be written as a sum of three squares. It is the sum of four but no fewer squares.

The BMW 327 was a touring car produced between 1937 and 1941.

Source: What's Special About This Number?

440

440 = 2³ x 5 x 11.

440 is the sum of the first 17 primes (2 to 59).

440 is divisible by the sum of its prime factors: 2 + 2 + 2 + 5 + 11 = 22.

440 is the number of permutations of 12 items that fix nine elements.

440 and 441 are two consecutive numbers, each divisible by a square.

440 is the number of yards in the quarter-mile race in track-and-field competitions.

Source: Prime Curios!

606

606 = 2 x 3 x 101.

606 is both a 11-gonal (hendecagonal) number and a centered 11-gonal (hendecagonal) number.

606 is 4411 in base 5.

606 is the sum of six consecutive primes: 606 = 89 + 97 + 101 + 103 + 107 + 109.

606 is the telephone area code the covers the eastern part of the state of Kentucky.

Source: What's Special About This Number?

303

303 = 3 x 101.

303 is the number of bipartite graphs on eight nodes (vertices).

303³ = 27,818,127, which is a concatenation of the cubes 1, 8, and 27.

303 is a divisor of 101² - 1.

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

In the Gregorian calendar, 303 is the number of years that are not leap years in a period of 400 years.

Source: What's Special About This Number?

521

521 is a prime number.

521 has a representation as a sum of two squares: 521 = 11² + 20².

521 is the 13th Lucas number.

521 and 523 for a twin prime pair.

521 is the hypotenuse of a primitive Pythagorean triple: 521² = 279² + 440².

521 has the representation 521 = 2⁹ + 9.

521 is the exponent of the Mersenne prime 2⁵²¹ - 1.

521 is the smallest prime whose reversal is a cube: 125 = 5³.

Galaxy cluster Abell 521 is located about 2.9 billion light-years from Earth.

Source: Prime Curios!

174

174 = 2 x 3 x 29.

174 is a divisor of 59² - 1.

174 is the number of twin primes among the first thousand primes.

174 = 7² + 5³.

174 is the smallest number that can be written as the sum of four positive distinct squares in six ways.

In 1978, Landon Noll and Laura Nickel used a CDC Cyber 174 to prove that the Mersenne number M₂₁₇₀₁ is a prime number.

Source: Prime Curios!