# Compare 21 vs 61

Property | 21 | 61 |
---|---|---|

Type | semiprime | prime |

Unique factors | 2 | 1 |

Total factors | 2 | 1 |

Prime factorization | 3^{1} × 7^{1} | 61^{1} |

Prime factorization | 3 × 7 | 61 |

Divisors count | 4 | 2 |

Divisors | 1, 3, 7, 21 | 1, 61 |

Number of properties | 1 | 12 |

Additive primes | 11th | |

Centered decagonal primes | 3rd | |

Centered square primes | 4th | |

Cuban primes 1 | 4th | |

Long primes | 8th | |

Primes | 18th | |

Pythagorean primes | 8th | |

Semiprimes | 7th | |

Sexy primes (1st member) | 12th | |

Sexy prime quadrupletss (1st member) | 4th | |

Sexy prime triplets (1st member) | 8th | |

Solinas primes | 15th | |

Twin primes (2nd member) | 7th | |

Roman numberals | XXI | LXI |

Base 2 | 10101_{2} | 111101_{2} |

Base 3 | 210_{3} | 2021_{3} |

Base 4 | 111_{4} | 331_{4} |

Base 5 | 41_{5} | 221_{5} |

Base 6 | 33_{6} | 141_{6} |

Base 7 | 30_{7} | 115_{7} |

Base 8 | 25_{8} | 75_{8} |

Base 9 | 23_{9} | 67_{9} |

Base 10 | 21_{10} | 61_{10} |

Base 11 | 1a_{11} | 56_{11} |

Base 12 | 19_{12} | 51_{12} |

Base 13 | 18_{13} | 49_{13} |

Base 14 | 17_{14} | 45_{14} |

Base 15 | 16_{15} | 41_{15} |

Base 16 | 15_{16} | 3d_{16} |