49081

This number is a prime.

+ In 1999, Harvey Dubner discovered that R49081 = (10^49081-1)/9 was a repunit probable prime.

+ 49081 is a cyclops prime. 49081 is the concatenation of 3 square numbers: 49=7^2; 0 =0^2 and 81=9^2 4908 (the first 4 digits) = 12*409. 409 is also the concatenation of 3 square numbers 4, 0 and 9 and also a holey cyclops prime. 409 has the same 3 digits as the first 3 digits of 49081. [Ruiz-Huidobro]

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