This number is a composite.
The smallest 2-digit number in which the sum of digits is equal to the sum of prime factors (27 = 3 * 3 * 3 and 3 + 3 + 3 = 9). [Russo]
Vaughan (1977) showed that all integers are the sum of at most 27 prime numbers.
2 and 7 are the smallest and largest single-digit primes.
2 + 3 + 4 + 5 + 6 + 7 = 27. [Stone]
The product of the first 27 Mersenne prime exponents (minus one) is a 27 reversed-digit prime.
Smaller of the smallest pair of consecutive numbers with 3 prime factors. [Gupta]
The smallest number that is both a Smith number and a SPRP for a base less than one hundred. [H. Brown]
The smallest composite number n > 1 such that n! +
1 is prime. [Capelle]
π(2!!) * π(7!!) = 27. [Firoozbakht]
27^27 + (2*7)^(2*7) is prime. [Silva]
π(27) = 2 + 7. [Kumar]
The smallest composite number which cannot be expressed as
the sum of two primes. [Wesolowski]
The only prime cube that is one less than an even perfect number. [Gudipati]
The sum of all composite digits (4+6+8+9) equals the first odd prime cubed. [Silva]
(There are 9 curios for this number that have not yet been approved by an editor.)
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