Tessarakontaheptaphobia (from Greek tessarakonta, "forty", and hepta, "seven") is the fear of number 47. This phobia is linked with 47 Conspiracy. Professor Donald Bentley of Pomona College, creator of Star Trek claimed that everything adds up to 47 or 74, as demonstrated in isosceles triangle in which two of the sides equal to the base side which is assigned as 47. This is commonly feared by Star Trek fans where the number is abundant in them. Sufferers would fear not just 47 alone, but 47 embedded in them, such as 247 and 6474. 47 could bring curse or bad luck to them, as well as signifying a bad signal, like having only 47 minutes till the certain death after suffering a life-threatening injury. 47 is unlucky number 13 away from 60, especially in time like 11:47pm, 13 minutes till midnight, which is widely the most dreaded time of the day.
Sufferers would try to avoid using number that has 47 in them and would dread when someone assign them that number. Some would avoid using pairs of numbers for those who believe that everything adds up to 47.