59996...19009 (27-digits)

This number is a composite.

                                               5999661 1749274758 4686619009

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This Carmichael number is the smallest of the form (k+1)(2k+1)(4k+1)(7k+1)(14k+1). Here, k = 28 x 2136. Note that 1,2,4,7 and 14 are the proper divisors of the Perfect number 28. [Hartley]