# LXXXI Roman Numeral

LXXXI is roman numeral 81. Hexadecimal, fibonacci sequence, prime numbers, square root, roman numeral converting for LXXXI roots and more.

### Read and Write Roman Numeral LXXXI

Roman numeral symbols are written and read from left to right, from highest to lowest values. If LXXXI is text, it is the number 81.

### Mathematics

Prime Factors: |
3 x 3 x 3 x 3 = 81 |

Factorial:
81! | 5.79712602075E+120 |

Harshad Number:
81 | True |

Triangular Number Of
81 | 3321 |

Square Root: √81 | 9 |

Cube Root (Root 3): ^{3}√81 | 4.32674871092 |

Tesseract Root (Root 4): ^{4}√81 | 3 |

Quintal / nth Root. (Root 5) ^{5}√81 | 2.40822468528 |

¾ Root | 27 |

Fibonnaci #
81 | 37889062373143906 |

Recipricol ^{1}/_{
81 } | 0.0123456790123 |

Quarter ^{1}/_{4} | 20.25 or ^{20.25}/_{81} |

Half ^{1}/_{2} | 40.50 or ^{40.50}/_{81} |

Third ^{1}/_{3} | 27 or ^{27}/_{81} |

### Roman Numeral Chart. Read & Write 81

Reading and writing roman numerals isn't common knowledge. However, this** roman numeral chart** should help you read and write numbers in roman numerals from 1 to 1,000,000. Using an overline symbol is times 1,000. ( Example: X means to add 3 zeros to your number. So X which is 5, but written as X with the overline is 5,000.

- When a symbol appears after a larger symbol it is added: Example: VI = V + I = 5 + 1 = 6
- When a symbol appears before a larger symbol it is subtracted: Example: IX = X - I = 10 - 1 = 9
- Do not use the same symbol more than 3 times. But, IIII is sometimes used for 4

1 | I | 10 | x | 500 | D | 1,001 | MI |

2 | II | 20 | XX | 501 | DI | 1,002 | MII |

3 | III | 30 | XXX | 530 | DXXX | 1,030 | MXXX |

4 | IV | 40 | XL | 550 | DL | 1,550 | MDL |

5 | V | 50 | L | 600 | DC | 1,555 | MDLV |

6 | VI | 60 | LX | 650 | DCL | 5,000 | V |

7 | VII | 70 | LXX | 700 | DCC | 10,000 | X |

8 | VIII | 80 | LXXX | 800 | DCCC | 50,000 | L |

9 | IX | 90 | XC | 890 | DCCCXC | 100,000 | C |

10 | X | 95 | XCV | 900 | CM | 500,000 | D |

11 | XI | 99 | XCIX | 950 | CML | 1,000,000 | M |

12 | XII... | 100 | C | 1000 | M |

39 | XXXIX |

37 | XXXVII |

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I published this page on Jan 15th, 2016 and last updated on August 13, 2017. © 2016 James Cordeiro of You Go Media. Numbers Finder - You Go Numbers!