Method names of long numbers used to denote extent of ten (the number of zeros after the unit). There is a long and short system names numbers. In Europe, mostly use the long system names.

Used short system, but a billion called *a billion*.

ten | |

STO | |

a thousand | |

million | |

billion | |

billion | |

Billiards | |

trillion (quintillion) | |

sextillion | |

septillion |

### Mersenne primes

### Prime numbers Fermat

Known Farm:

### Simple numbers-twins

### Factoral simple

2, 3, 5, 7, 23, 719, 5 039, 39 916 801, 479 001 599, 87 178 291 199.