# Compare 18 vs 31

Property | 18 | 31 |
---|---|---|

Type | composite number | prime |

Unique factors | 2 | 1 |

Total factors | 3 | 1 |

Prime factorization | 2^{1} × 3^{2} | 31^{1} |

Prime factorization | 2 × 3 × 3 | 31 |

Divisors count | 6 | 2 |

Divisors | 1, 2, 3, 6, 9, 18 | 1, 31 |

Number of properties | 0 | 18 |

Centered decagonal primes | 2nd | |

Centered triangular primes | 2nd | |

Chen primes | 11th | |

Class 1+ primes | 8th | |

Emirps | 3rd | |

Euclid primes | 4th | |

Happy primes | 5th | |

Lucky primes | 4th | |

Mersenne primes | 3rd | |

Multiplicative primes | 7th | |

Pierpont primes of the 2nd kind | 8th | |

Primes | 11th | |

Right-truncatable primes | 7th | |

Sexy primes (1st member) | 7th | |

Sexy prime triplets (1st member) | 5th | |

Solinas primes | 10th | |

Super primes | 5th | |

Twin primes (2nd member) | 5th | |

Roman numberals | XVIII | XXXI |

Base 2 | 10010_{2} | 11111_{2} |

Base 3 | 200_{3} | 1011_{3} |

Base 4 | 102_{4} | 133_{4} |

Base 5 | 33_{5} | 111_{5} |

Base 6 | 30_{6} | 51_{6} |

Base 7 | 24_{7} | 43_{7} |

Base 8 | 22_{8} | 37_{8} |

Base 9 | 20_{9} | 34_{9} |

Base 10 | 18_{10} | 31_{10} |

Base 11 | 17_{11} | 29_{11} |

Base 12 | 16_{12} | 27_{12} |

Base 13 | 15_{13} | 25_{13} |

Base 14 | 14_{14} | 23_{14} |

Base 15 | 13_{15} | 21_{15} |

Base 16 | 12_{16} | 1f_{16} |