510
This number is a composite.
The concatenation of 510 with itself (510510) is the product of the first 7 primes and also the product of the 7th through 10th Fibonacci numbers (13, 21, 34, and 55). [Zerger]
(Continuing the previous curio) The difference between the next prime (19) and the next Fibonacci number (89 - also a prime) is 70, which is the product of the Fibonacci subscripts above. [Trotter]
(There are 2 curios for this number that have not yet been approved by an editor.)
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