In Mathematics
Forty-seven is the fifteenth prime number, a safe prime, the thirteenth supersingular prime, and the sixth Lucas prime. Forty-seven is a highly cototient number. It is an Eisenstein prime with no imaginary part and real part of the form .
It is a Lucas number. Because its digits appear as successive terms earlier in the series of Lucas numbers: 2, 1, 3, 4, 7, 11, 18, 29, 47… ; it is also a Keith number.
Forty-seven is a strictly non-palindromic number.
Its representation in binary being 00101111, 47 is a prime Thabit number, and as such is related to the pair of amicable numbers {17296, 18416}.
Forty-seven is a Carol number.
Read more about this topic: 47 (number)
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