Vampire Numbers

The number $1827$ is an interesting number, because 1827 = 21 \times 87, and all of the same digits appear on both sides of the $=$. The number $136948$ has the same property: 136948 = 146 \times 938.

Such numbers are called Vampire Numbers. More precisely, a number $v$ is a Vampire Number if it has a pair of factors, $a$ and $b$, where a \times b = v, and together, $a$ and $b$ have exactly the same digits, in exactly the same quantities, as $v$. None of the numbers $v$, $a$, or $b$ can have leading zeros. The mathematical definition states that $v$ should have an even number of digits and that $a$ and $b$ should have the same number of digits, but for the purposes of this problem, we will relax that requirement, and allow $a$ and $b$ to have differing numbers of digits, and $v$ to have any number of digits. Here are some more examples:

126 = 6 \times 21, 10251 = 51 \times 201, 702189 = 9 \times 78021, 29632 = 32 \times 926

Given a number $X$, find the smallest Vampire Number which is greater than or equal to $X$.