65 (another Prime Pages' Curiosity)
 Curios: Curios Search:   Participate: GIMPS has discovered a new largest known prime number: 282589933-1 (24,862,048 digits) The first 65 digits of 6565 form a prime number. [Honaker] The product of the first two primes of the form 4n + 1. Euler found 65 integers, which he called "numeri idonei," that could be used to prove the primality of certain numbers. [Brown] 665 - 5 is the smallest prime of the form ac - b, where b = a - 1. Note that c is the concatenation of a and b. [Kulsha] The smallest composite number of the form n2 + 1, where n is even. 65 is the ONLY number which gives a prime square, on adding as well as subtracting its reverse from it (65 + 56 = 112, 65 - 56 = 32). [Gupta] The only number which is the difference of fourth powers of two primes. [Murthy] (65!)2 + 1 is prime. [Dobb] 65 = 5 * 13 and (65) = (5) * (13) = 5 + 13. [Honaker] The smallest Fermat semiprime. [Capelle] (65) = phi(65) - 6*5. [Langroudi] (There is one curio for this number that has not yet been approved by an editor.) Prime Curios! © 2000-2019 (all rights reserved)  privacy statement   (This page was generated in 0.0363 seconds.)