2015

2015 = 5 x 13 x 31.

2015 is palindromic in base 2 (binary): 11111011111 (A030130 and A168355). 2015 repeats the string 133 in base 4: 133133 (A020332). It repeats the string 37 in base 8: 3737 (A020336).

2015 is a Lucas-Carmichael number (A006972 and A129868).

2014, 2015, and 2016 each have three distinct prime factors (sphenic numbers) (A168626).

2015 is the sum of 10 distinct powers of 2 (A038461).

2015 is a number that cannot be written as a sum of three squares.

2015 divides 92⁴ - 1.

2015 is a year with exactly three "Friday the 13ths" (A190653).

2015 is a year in which a blue moon occurs (a second full month to occur in a single calendar month) (A125680).

The year 2015 is the 100th anniversary of the founding of the Mathematical Association of America.

Source: OEIS

1834

1834 = 2 x 7 x 131.

1834 is an octahedral number (A005900).

1834 is the sum of the cubes of the first five primes (A098999).

1834 is a number that has more different digits than its square (A061277).

1834 is 3452 in base 8.

1834 divides 99¹³ - 1.

Source: What's Special About This Number?

8242

8242 = 2 x 13 x 317.

Concatenating 8242 with 1 less than 8242 produces a square (A054214 and A054215): 82428241 = 9079².

The base 4 representation of 8242 has 4 zeroes, 2 twos, and no ones (A045033 and A045059): 2000302.

8242 has two representations as a sum of two squares: 8242 = 41² + 81² = 59² + 69².

Source: What's Special About This Number?

2445

2445 = 3 x 5 x 163.

2445 is a truncated tetrahedral number (A005906).

2445 is a number n such that n! has a square number of digits (A006488).

2445 is the sum of nine nonzero 6th powers (A003365).

2445 is a lucky number that is divisible by the sum of its digits (A118564).

2445 divides 59⁶ - 1.

Source: What's Special About This Number?

1767

1767 = 3 x 19 x 31. The sum 3 + 19 + 31 = 53 is a prime number (A176877).

1767 is 123213 in base 4.

1767 is the sum of the digit reversals of the first 47 natural numbers (A062918).

1767 is a number n such that n, n + 1, and the sum of these two numbers each have three distinct prime factors (A168629).

1767 divides 94² - 1.

Source: OEIS

8666

8666 = 2 x 7 x 619.

8666 has a 9th root whose decimal part starts with the digits 1 to 9 in some order.

8666 is a beastly number (A051003).

8666 is the number of permutations of length 21 that avoid the patterns 123 and 4312 (A116699).

8666 is a number n such that n, n + 1, n + 2, and n + 3 are not divisible by any of their nonzero digits (A244358).

8666 is a number n such that n ends with 6 and is the difference of cubes in at least one way (A038861).

Source: What's Special About This Number?

1295

1295 = 5 x 7 x 37.

1295 is 5555 in base 6 (A097252).

1295 has the representation 6⁴ - 1 (A123865 and A024062). It is a subperfect power (A045542).

1295 is the sum of consecutive cubes (A217843).

1295 is the difference of two positive fourth powers (A147857).

Every run of digits of 1295 in base 4 has length 2 (A033002): 110033.

Source: What's Special About This Number

3201

3201 = 3 x 11 x 97.

3201 is an octagonal number (A000567).

3201 is the number of regions in a regular 33-gon that are hexagons (A067153).

3201 is the sum of the first 22 Sophie Germain primes (A066819).

3201 divides 98² - 1.

3201 is 12222 in base 7.

Source: OEIS

1833

1833 = 3 x 13 x 47.

1833 is the first of two consecutive sphenic numbers (A215217).

The 1833rd triangular number is palindromic (A008509): 1680861.

1833 is the start of the first run of exactly 7 consecutive odd composite numbers (A075067).

1833 divides 95⁶ - 1.

Source: OEIS

6306

6306 = 2 x 3 x 1051.

6306 is the sum of three consecutive semiprimes (A173968).

6306 divides 55²⁵ - 1.

6306 is the first of a triplet of consecutive squarefree numbers each of which has exactly three distinct prime factors (A242606).

Source: OEIS

5453

5453 = 7 x 19 x 41.

5453 is a potential magic constant of a 7 x 7 magic square composed of consecutive primes (A188536).

5453 is a number such that the number of 3s in base 5 is 4 (A043364): 133303.

5453 divides 83⁶ - 1.

Source: OEIS

4220

4220 = 2 x 5 x 211.

4220 is a number n for which the sum of the first n composite numbers is a palindrome (A053779).

4220 is the maximum number of regions the plane is divided into by 38 triangles (A077588).

4220 is the number of binary rooted trees with 39 nodes and internal path length 39 (A108643).

4220 divides 71¹⁰ - 1.

Source: What's Special About This Number?

5558

5558 = 2 x 7 x 397.

5558 is the smallest number whose digital product is equal to 10³ (A089386).

5558 is 1010110110110 in base 2 (binary) and 21121212 in base 3. It is 12666 in base 8 (A043447) and 7555 in base 9 (A043475). 5558 is 2050 in base 14.

5558 is a number n such that 1 + n + n³ + n⁵ + n⁷ + n⁹ + . . . + n⁴¹ is prime (A244386).

5558 is a value n such that 90n + 11, 90n + 13, 90n + 17, 90n + 19 are all primes (A051897).

5558 is an integer n such that 6n -/+ 1 and 30n -/+ 1 are all primes (A216847).

5558 divides 79⁹ - 1.

Source: OEIS

1599

1599 = 3 x 13 x 41.

1599 is 22344 in base 5 and 11223 in base 6. It is 4443 in base 7 (A032831).

1599 is a number n such that the square of n is the sum of two or more consecutive squares (A097812).

1599 is the sum of three consecutive pentagonal numbers (A129863).

1599 is a happy-go-lucky number; it is both happy and lucky (A091431).

Source: OEIS

7777

7777 = 7 x 11 x 101. It is a palindrome with exactly three distinct palindromic prime factors (A046409).

7777 has the representation 6⁵ + 1 (A062394). It is 100001 (palindromic) in base 6 (A029963 and A033043).

7777 divides 36⁵ - 1.

7777 is a number that is the sum of two positive fifth powers (A003347 and A004842).

7777 is a Kaprekar number (A006886).

Source: OEIS

1902

1902 = 2 x 3 x 317.

1902 has cube that contains only even digits (A052004).

1902 is a number n such that 2n - 1, 4n - 1, and 6n - 1 are primes (A124486).

1902 is the sum of three consecutive semiprimes (A173968).

1902 is the number of primes p such that 8! - p is prime (A140088).

1902 is a year with exactly one "Friday the 13th" (A190651).

Source: What's Special About This Number?

1898

1898 = 2 x 13 x 73.

1898 is 1122 in base 12 (A033010). It is 868 in base 15.

1898 is the smallest multiple of 26 whose digits sum to 26 (A002998).

1898 is the number of primes between 26² and 26³ (A079648).

1898 is the least positive integer that can be represented as the sum of a semiprime and a square in exactly 25 ways (A101181).

1898 has two representations as a sum of two squares: 1898 = 7² + 43² = 23² + 37². It is the sum of two squared primes in exactly two ways (A226539).

1898 divides 81³ - 1.

Source: OEIS

8763

8763 = 3 x 23 x 127.

8763 and its successor have the same digits in their prime factorization (A061665).

8763 is the number of partitions of 38 having not more odd than even parts (A171966).

8763 is a number n such that 4n + 1 is a palindromic prime (A192261).

8763 divides 22¹⁸ - 1.

Source: What's Special About This Number?

5235

5235 = 3 x 5 x 349.

The product of the digits of 5235 is ten times their sum (A062043).

The sum of the cubes of the digits of the cube of 5235 is a perfect cube (A164882).

5235 is a lucky number with only prime digits (A118718).

5235 is the smaller of two consecutive lucky numbers with the same digital sum (A118566).

5235 and its reversal (5325) are both multiples of 15 (A062905).

5235 divides 31²⁹ - 1.

Source: OEIS

5735

5735 = 5 x 31 x 37.

5735 is a pentagonal number (A049452 and A014632).

5735 is a number divisible by 5 that is the difference between two different positive cubes in at least one way (A038853).

5735 is a number whose set of base 11 digits is {3, 4} (A032835): 4344.

5735 is a number n such that 2n + 1, 3n + 2, and 4n + 3 are primes (A126995).

5735 divides 26⁶ - 1.

5735 is a number that cannot be written as a sum of three squares.

Source: Number Gossip