Consider all the natural numbers up to one million and ask the following question:
What numbers are comprised of the same set of digits as comprise its prime factors? It turns out that 132 is the first such number:
These types of numbers comprise OEIS A035141:
A035141 | Composite numbers |
There are 96 such numbers in the range up to 40,000:
132, 312, 735, 1255, 1377, 1775, 1972, 3792, 4371, 4773, 5192, 6769, 7112, 7236, 7371, 7539, 9321, 11009, 11099, 11132, 11163, 11232, 11255, 11375, 11913, 12176, 12326, 12595, 12955, 13092, 13175, 13312, 13377, 13491, 13755, 14842, 15033, 15303, 15317, 15532, 16332, 17272, 17276, 17343, 17482, 17973, 17975, 19075, 19276, 20530, 21345, 21372, 22413, 22714, 23535, 24338, 25030, 25105, 27232, 27393, 27944, 31007, 31317, 31419, 31479, 31503, 31592, 31722, 31977, 32024, 32104, 32145, 32612, 32973, 33011, 33327, 33781, 33925, 34112, 34997, 35213, 35262, 35722, 36882, 37115, 37127, 37317, 37359, 37522, 37662, 37741, 37791, 37921, 38385, 39172, 39795
However, it can be restated that 735 is very special, if not unique, because its prime factors (without multiplicity) of 3, 5 and 7 are the same as the digits of the number.
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