1571
This number is a prime.
1571 is the only known prime of form (p!/p# + 1)/p. [Luhn]
1571 = prime(π(1!!*5!!*7!!*1!!)). It is the only known multidigit number with this property. [Firoozbakht]
The smallest prime whose square (2468041) contains all of the even digits. [Gaydos]
The smallest prime congruent to 11 (mod 24) that is not a full reptend prime in base 6. [Nie]
(There is one curio for this number that has not yet been approved by an editor.)
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