# Compare 19 vs 21

Property | 19 | 21 |
---|---|---|

Type | prime | semiprime |

Unique factors | 1 | 2 |

Total factors | 1 | 2 |

Prime factorization | 19^{1} | 3^{1} × 7^{1} |

Prime factorization | 19 | 3 × 7 |

Divisors count | 2 | 4 |

Divisors | 1, 19 | 1, 3, 7, 21 |

Number of properties | 18 | 1 |

Centered triangular primes | 1st | |

Chen primes | 8th | |

Cousin primes (1st member) | 4th | |

Cuban primes 1 | 2nd | |

Happy primes | 3rd | |

Long primes | 3rd | |

Pierpont primes | 7th | |

Primes | 8th | |

Prime quadruplets (4th member) | 2nd | |

Prime quintuplet 1s (5th member) | 1st | |

Prime quintuplet 2s (4th member) | 2nd | |

Prime sextuplets (5th member) | 1st | |

Prime triplets (2nd member) | 5th | |

Prime triplets (3rd member) | 4th | |

Semiprimes | 7th | |

Sexy primes (2nd member) | 4th | |

Sexy prime triplets (3rd member) | 2nd | |

Solinas primes | 7th | |

Twin primes (2nd member) | 4th | |

Roman numberals | XIX | XXI |

Base 2 | 10011_{2} | 10101_{2} |

Base 3 | 201_{3} | 210_{3} |

Base 4 | 103_{4} | 111_{4} |

Base 5 | 34_{5} | 41_{5} |

Base 6 | 31_{6} | 33_{6} |

Base 7 | 25_{7} | 30_{7} |

Base 8 | 23_{8} | 25_{8} |

Base 9 | 21_{9} | 23_{9} |

Base 10 | 19_{10} | 21_{10} |

Base 11 | 18_{11} | 1a_{11} |

Base 12 | 17_{12} | 19_{12} |

Base 13 | 16_{13} | 18_{13} |

Base 14 | 15_{14} | 17_{14} |

Base 15 | 14_{15} | 16_{15} |

Base 16 | 13_{16} | 15_{16} |