Last time we’ve seen some popular fictional passwords, and how they are used in Exploit.in – a collection of 739,861,478 leaked passwords. I wanted to take another look at some popular numbers and how they are used in passwords.

# π

How many digits of Pi have you memorized? I’ve got 6 digits after the decimal: `3.141592`

. Not bad, but could be better. Let’s see how far the Exploit.in community takes it:

17,713 password have exactly 7 decimal places of Pi (`1415926`

). 1,626 have 10 decimal digits. The record is a single password with **37** digits of Pi – `1415926535 8979323846 2643383279 502884179`

. The last two digits in that password are cunningly reversed (`79`

instead of `97`

), so unfortunately they don’t count.

Here’s a breakdown for the digits of Pi in passwords:

# Math constants

Same as with Pi, I’m only considering digits after the decimal point:

Value | Digits | Passwords |
---|---|---|

e | 7182818284 | 337 |

e | 71828182845904523536 | 7 |

√2 | 4142135623 | 114 |

√3 | 7320508075 | 21 |

Phi | 6180339887 | 86 |

Euler Mascheroni | 5772156649 | 1 |

Didn’t make it: Conway’s Constant, Khinchin’s constant, and Glaisher Kinkelin.

# Fibonacci sequence

One advantage of the Fibonacci sequence is that if you forget your password you can always calculate it. 25,316 unforgettable passwords contain 8 Fibonacci numbers (1 through 21). Only 4 passwords make it all the way to the 15th number, 610:

# Physics and Chemistry constants

Number | Digits | Passwords | |
---|---|---|---|

Light Speed | Meters/Second | 299792458 | 1988 |

Light Speed | Miles/Second | 186282 | 298 |

Light Speed | Kilometers/Second | 299792 | 2561 |

Light Speed | Miles/Hour | 670616629 | 1 |

Avogadro | 6.02×10^{23} |
6021023 | 259 |

Avogadro | 6.022×10^{23} |
60221023 | 73 |

Avogadro passwords that make good use of special characters include `m602x1023e`

and `602*1023`

.

# Pop-culture numbers

Unsurprisingly, numbers that appear on TV or song lyrics make their appearance in passwords. I couldn’t find too many examples:

## Music

Tommy Tutone | 867-5309 / Jenny | 8675309 (Exact password) | 13894 |

Tommy Tutone | 868-5309 / Jenny | 8675310 (contain) | 28231 |

Queens of the Stone Age | Regular John | 16278263789 | 7 |

## LOST

40,430 passwords are exactly `4815162342`

. Additional 34,318 password *contain* `4815162342`

, and another 1,058 passwords have The Numbers with separators, for example `L48O1516S2342T`

.

# See also

For a more serious analysis of password trends and common patterns:

- Analyzing the Patterns of Numbers in 10 Million Passwords – By Max Woolf
- How are users choosing their passwords on the internet?
- Why So Many People Make Their Password ‘Dragon’ – By Louise Matsakis, Wired (warning: soft paywall)
- Unmasked: What 10 million passwords reveal about the people who choose them