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Proprietà matematiche
È il nono numero primo, after 19 and before 29.
It is a prime factorial, 4! - 1.
It is a safe prime number, that is to say (23-1)/2 it is still a prime number.
It is a Woodall prime number.
It's a Wedderburn-Etherington number.
It is the second issue of Smarandache-Wellin, base concatenation 10 of the first three prime numbers,[...]