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+ The largest 3-digit prime that can be written as the sum of 15 consecutive primes: 29 + 31 + 37 + 41 + 43 + 47 + 53 + 59 + 61 + 67 + 71 + 73 + 79 + 83 + 89.

+ Weintraub discovered that 6505941701960039 is followed by exactly 863 composites. This was the largest prime gap explicitly calculated at the time.

+ 863 = (11 + 71) + (11 * 71). Note that 11, 71 and 863 are primes. [Capelle]

+ sigma(863) = phi(prime(8)*prime(6)*prime(3)). It is the only known multidigit such prime (up to 2*10^8). [Firoozbakht]

+ Lucas(863) is prime. The largest three-digit prime index for which this is true. [Schiffman]

+ There are exactly 863 four-digit odd semiprimes with all distinct digits. [Bajpai]

(There are 2 curios for this number that have not yet been approved by an editor.)




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