This number is a prime.
109 = 1*2+3*4+5*6+7*8+9. [Silva]
Shibuya 109 is a trend setting fashion complex for young women in Tokyo, Japan. One of the buildings there is called "The Prime." [Anansi]
109 can be expressed as 22 * 33 + 1. [Patterson]
The Caldwell Catalog contains 109 deep-sky delights for backyard stargazers.
The Sun is just over 109 times the diameter of the Earth. [Friedman]
109 = prime(prime (1+0+9)). Note that 109 is the only number with this property. [Firoozbakht]
109 = (7^3-5^3)/2 is the smallest prime which equals to one half of the difference of cubes of primes. [Simon]
There are 109 letters in the following quotation: "Given the millennia that people have contemplated prime numbers, our continuing ignorance concerning the primes is stultifying." R. Crandall and C. Pomerance, from Prime Numbers: A Computational Perspective, Springer-Verlag, 2001. [Post]
The smallest number (coincidentally prime) that has more distinct digits than its square. [Capelle]
The smallest prime of the form 10^(2k)+10^k-1. Those primes consist of 1 followed by k 0's and k 9's. [Silva]
The smallest non-trivial prime that is the sum of the reversal of two consecutive primes (109 = R(47) + R(53) = 74 + 35). [Meller]
Smallest multidigit prime which is a partial sum of digital reversals of n: 0 + 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 1 + 11 + 21 + 31 = 109 is prime. [Post]
The sum of the reversals of any two double-digit numbers summed to a hundred. [Loungrides]
109 is as easy as 1^1 + 2^2 * 3^3. [Meyers]
109 = (10*9) + (10+9). [Bui Quang Tuan]
Convert 109 to binary to get 1101101 and treat it as a decimal number; 1101101 = 109*10101 = 92 and 10101 itself is a binary number. [Bergot]
The smallest prime concatenated from two successive numbers, (9, 10), that are sides in an equable triangle. (A shape is called equable if its area equals its perimeter). The triangle is (9, 10, 17). [Loungrides]
Consider the cubic equation x^3-15x-4=0, which has real coefficients, and three real roots for its answers. If we apply Cardano's formula to this problem, using a=1, b=0, c=-15, d=-4, we find taking the square root of negative 109 in the resulting computation is required!
109 has a partition whose parts concatenate to its cube: 109 = 1 + 29 + 50 + 29 -> 1295029 = 1093. [Beedassy]
None of the 109 consecutive integers from 6498130362 to 6498130470 are semiprimes. [Gaydos]
A new species of butterfly was discovered in Israel for the first time in 109 years. [Homewood]
109 turned upside down is the 109th odd prime number. [Honaker]