Vampire Number Calculator

Input a number to check if it is a Vampire Number or enter a start and end range to generate all Vampire Numbers within that range.

Vampire Number Check or Generate

What is a Vampire Number?

A Vampire Number is a special number formed by rearranging the digits of two factors (known as fangs), which are equal-length integers. Specifically, a Vampire Number \(N\) satisfies the following properties: \( N = x \times y \) Where:

  • \(x\) and \(y\) (the "fangs") have the same number of digits, and their combined digit count equals the number of digits in \(N\). For example, if \(N\) is a 4-digit number, \(x\) and \(y\) must each have 2 digits.
  • Neither \(x\) nor \(y\) can have trailing zeros unless both are zero.
  • The digits of \(x\) and \(y\), when combined, must be identical to the digits of \(N\).

How to Identify a Vampire Number

To determine if a number \(N\) is a Vampire Number:

  1. Check the digit count: If \(N\) has an odd number of digits, it cannot be a Vampire Number.
  2. Find suitable factor pairs: Identify factor pairs \(x\) and \(y\) such that \(x \times y = N\). Ensure \(x\) and \(y\) have equal digit counts, and neither ends with 0 simultaneously.
  3. Compare digit combinations: Combine the digits of \(x\) and \(y\), then compare with the digits of \(N\). If the digit combinations match perfectly, \(N\) is a Vampire Number.

Examples

Example 1: Is 1023 a Vampire Number?

Solution:

1. Digit count check:

1023 has 4 digits, so it may be a Vampire Number.

2. Find factor pairs:

Possible factor pairs with equal digit counts:

\(11 \times 93 = 1023\)

\(31 \times 33 = 1023\)

3. Compare digit combinations:

For \(11\) and \(93\): The digits are \(1, 1, 9, 3\), but \(1023\) has digits \(1, 0, 2, 3\). No match.

For \(31\) and \(33\): The digits are \(3, 1, 3, 3\), but \(1023\) has digits \(1, 0, 2, 3\). No match.

Result: 1023 is not a Vampire Number.

Example 2: Is 1260 a Vampire Number?

Solution:

1. Digit count check:

1260 has 4 digits, so it may be a Vampire Number.

2. Find factor pairs:

Possible factor pairs:

\(14 \times 90 = 1260\)

\(15 \times 84 = 1260\)

\(18 \times 70 = 1260\)

\(20 \times 63 = 1260\)

\(21 \times 60 = 1260\)

\(28 \times 45 = 1260\)

\(30 \times 42 = 1260\)

\(35 \times 36 = 1260\)

3. Compare digit combinations:

The digits of \(21\) and \(60\) (\(2, 1, 6, 0\)) match perfectly with the digits of \(1260\).

Result: 1260 is a Vampire Number.

Example 3: Is 126000 a Vampire Number?

Solution:

1. Digit count check:

126000 has 6 digits, so it may be a Vampire Number.

2. Find factor pairs:

Possible factor pairs include:

(144, 875), (168, 750), (175, 720), (225, 560), (240, 525), (250, 504), (252, 500), (315, 400), (336, 375), (375, 336), (400, 315), (500, 252), (504, 250), (525, 240), (560, 225), (720, 175), (750, 168), (875, 144)

3. Compare digit combinations:

None of these factor pairs match the digit combination \(1, 2, 6, 0, 0, 0\).

ResultResult

First 100 Vampire Numbers

  • 1260
  • 1395
  • 1435
  • 1530
  • 1827
  • 2187
  • 6880
  • 102510
  • 104260
  • 105210
  • 105264
  • 105750
  • 108135
  • 110758
  • 115672
  • 116725
  • 117067
  • 118440
  • 120600
  • 123354
  • 124483
  • 125248
  • 125433
  • 125460
  • 125500
  • 126027
  • 126846
  • 129640
  • 129775
  • 131242
  • 132430
  • 133245
  • 134725
  • 135828
  • 135837
  • 136525
  • 136948
  • 140350
  • 145314
  • 146137
  • 146952
  • 150300
  • 152608
  • 152685
  • 153436
  • 156240
  • 156289
  • 156915
  • 162976
  • 163944
  • 172822
  • 173250
  • 174370
  • 175329
  • 180225
  • 180297
  • 182250
  • 182650
  • 186624
  • 190260
  • 192150
  • 193257
  • 193945
  • 197725
  • 201852
  • 205785
  • 211896
  • 213466
  • 215860
  • 216733
  • 217638
  • 218488
  • 226498
  • 226872
  • 229648
  • 233896
  • 241564
  • 245182
  • 251896
  • 253750
  • 254740
  • 260338
  • 262984
  • 263074
  • 284598
  • 284760
  • 286416
  • 296320
  • 304717
  • 312475
  • 312975
  • 315594
  • 315900
  • 319059
  • 319536
  • 326452
  • 329346
  • 329656
  • 336550
  • 336960