The Boeing 727 became the first three-engine jet built for commercial service.
727 = 1! + (1 + 2)! + (1 + 2 + 3)!. [Van Doorn]
The smallest odd prime that can be represented as the sum of a cube and its reversal (512 + 215). [Gupta]
The first prime whose square (528529) can be represented as the concatenation of two consecutive numbers. [De Geest]
Problably the only palindromic prime that can be expressed by the form n!+(n+1). [Silva]
727 starts the first chain of four palindromic primes, each formed from the previous one in forward and reverse order: 727, 72727, 727272727, 72727272727272727. [Silva]
The sum of the first five three-digit primes with midlle digit zero. [Silva]
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