1911

1911 = 3 x 7 x 7 x 13.

1911 is 11101110111 in base 2 (binary) (A023691), 131313 in base 4 (A037576), and 1133 in base 12 (A033010). It is 876 in base 15 and 777 in base 16 (A033029).

1911 is a hendecadonal number (A051682). It is also a heptagonal pyramidal number (A002413).

1911 divides 79³ - 1.

1911 was a year with exactly two "Friday the 13ths" (A190652).

Source: What's Special About This Number?

715

715 = 5 x 11 x 13.

715 is the tenth pentatope number. It is also a pentagonal number (A000326), a hendecagonal number (A051682), and a hexagonal pyramidal number (A002412).

715 is 222111 in base 3, 23023 in base 4, and 1313 in base 8.

715 is the number of intersections of diagonals in the interior of a regular 13-gon (A006561).

715 is the smallest positive number that can be written as a sum of distinct Fibonacci numbers in 26 ways.

Source: Number Gossip

960

960 = 2⁶ x 3 x 5.

960 is equal to the sum of its digits plus the sum of the cubes of its digits: 960 = 9 + 6 + 0 + 9³ + 6³ + 0³.

960 is 1111000000 in base 2 (binary), 33000 in base 4, and 1700 in base 8. The representations of 960 in bases 2, 3, 4, 5, 6, 8, and 10 all end in 0.

960 is the sum of six consecutive primes: 960 = 149 + 151 + 157 + 163 + 167 + 173.

960 is a hendecagonal number.

Source: What's Special About This Number?

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?

506

506 = 2 x 11 x 23.

506 is a pronic number because it is the product of two consecutive integers: 22 x 23 = 506.

506 is the sum of the first eleven squares: 1² + 2² + . . . + 10² + 11² = 506 (which makes it a square pyramidal number).

506 is a hendecagonal number.

The telephone area code 506 covers the Canadian province of New Brunswick.

Source: Number Gossip