Numerophobia, arithmophobia or mathematics anxiety is an anxiety disorder, where the condition is fear of dealing with numbers or mathematics. Sometimes numerophobia refers to fear of particular numbers. Fears of specific numbers Tetraphobia – fear of 4 Triskaidekaphobia – fear of 13 Heptadecaphobia - fear of 17 23 enigma – fear of 23 Curse of 39 - fear of 39 Hexakosioihexekontahexaphobia - fear of 666 Number related superstitions in music Curse of the ninth 27 Club References Phobias Superstitions about numbers