27387 is the lesser of a pair of adjacent composite numbers such that both are only one step away from their home primes. 27387 gives 3317179 which is prime and 27388 = 2^2 * 41 * 167 --> 2241167 which is also prime. See Bespoken for Sequences entry.

27387 is a member of OEIS A052018: numbers k with the property that the sum of the digits of k is a substring of k. Here the sum of the digits is 27. The members of the sequence from 27387 to 40000 is as follows:

[27387, 27396, 27459, 27468, 27477, 27486, 27495, 27549, 27558, 27567, 27576, 27585, 27594, 27639, 27648, 27657, 27666, 27675, 27684, 27693, 27729, 27738, 27747, 27756, 27765, 27774, 27783, 27792, 27819, 27828, 27837, 27846, 27855, 27864, 27873, 27882, 27891, 27909, 27918, 27920, 27921, 27922, 27923, 27924, 27925, 27926, 27927, 27928, 27929, 27936, 27945, 27954, 27963, 27972, 27981, 27990, 28099, 28189, 28198, 28208, 28218, 28228, 28238, 28248, 28258, 28268, 28278, 28279, 28288, 28297, 28298, 28369, 28378, 28387, 28396, 28459, 28468, 28477, 28486, 28495, 28549, 28558, 28567, 28576, 28585, 28594, 28639, 28648, 28657, 28666, 28675, 28684, 28693, 28729, 28738, 28747, 28756, 28765, 28774, 28783, 28792, 28819, 28820, 28821, 28822, 28823, 28824, 28825, 28826, 28827, 28828, 28829, 28837, 28846, 28855, 28864, 28873, 28882, 28891, 28909, 28918, 28927, 28936, 28945, 28954, 28963, 28972, 28981, 28990, 29099, 29189, 29198, 29207, 29217, 29227, 29237, 29247, 29257, 29267, 29277, 29279, 29287, 29288, 29297, 29369, 29378, 29387, 29396, 29459, 29468, 29477, 29486, 29495, 29549, 29558, 29567, 29576, 29585, 29594, 29639, 29648, 29657, 29666, 29675, 29684, 29693, 29720, 29721, 29722, 29723, 29724, 29725, 29726, 29727, 29728, 29729, 29738, 29747, 29756, 29765, 29774, 29783, 29792, 29819, 29828, 29837, 29846, 29855, 29864, 29873, 29882, 29891, 29909, 29918, 29927, 29936, 29945, 29954, 29963, 29972, 29981, 29990, 30000, 30106, 30116, 30126, 30136, 30146, 30156, 30166, 30176, 30186, 30196, 30610, 30611, 30612, 30613, 30614, 30615, 30616, 30617, 30618, 30619, 30999, 31006, 31015, 31024, 31033, 31042, 31051, 31060, 31105, 31106, 31115, 31124, 31125, 31133, 31135, 31142, 31145, 31151, 31155, 31160, 31165, 31175, 31185, 31195, 31206, 31215, 31224, 31233, 31242, 31251, 31260, 31306, 31315, 31324, 31333, 31342, 31351, 31360, 31406, 31415, 31424, 31433, 31442, 31451, 31460, 31506, 31510, 31511, 31512, 31513, 31514, 31515, 31516, 31517, 31518, 31519, 31524, 31533, 31542, 31551, 31560, 31606, 31615, 31624, 31633, 31642, 31651, 31660, 31706, 31715, 31724, 31733, 31742, 31751, 31760, 31806, 31815, 31824, 31833, 31842, 31851, 31860, 31906, 31915, 31924, 31933, 31942, 31951, 31960, 31999, 32069, 32078, 32087, 32096, 32104, 32114, 32124, 32134, 32144, 32154, 32164, 32169, 32174, 32178, 32184, 32187, 32194, 32196, 32269, 32278, 32287, 32296, 32369, 32378, 32387, 32396, 32410, 32411, 32412, 32413, 32414, 32415, 32416, 32417, 32418, 32419, 32469, 32478, 32487, 32496, 32569, 32578, 32587, 32596, 32669, 32678, 32687, 32696, 32769, 32778, 32787, 32796, 32869, 32878, 32887, 32896, 32969, 32978, 32987, 32996, 32999, 33103, 33113, 33123, 33133, 33143, 33153, 33163, 33173, 33183, 33193, 33310, 33311, 33312, 33313, 33314, 33315, 33316, 33317, 33318, 33319, 33999, 34102, 34112, 34122, 34132, 34142, 34152, 34162, 34172, 34182, 34192, 34210, 34211, 34212, 34213, 34214, 34215, 34216, 34217, 34218, 34219, 34999, 35101, 35110, 35111, 35112, 35113, 35114, 35115, 35116, 35117, 35118, 35119, 35121, 35131, 35141, 35151, 35161, 35171, 35181, 35191, 35999, 36010, 36011, 36012, 36013, 36014, 36015, 36016, 36017, 36018, 36019, 36100, 36110, 36120, 36130, 36140, 36150, 36160, 36170, 36180, 36190, 36209, 36219, 36229, 36239, 36249, 36259, 36269, 36279, 36289, 36299, 36920, 36921, 36922, 36923, 36924, 36925, 36926, 36927, 36928, 36929, 36999, 37208, 37218, 37228, 37238, 37248, 37258, 37268, 37278, 37288, 37298, 37820, 37821, 37822, 37823, 37824, 37825, 37826, 37827, 37828, 37829, 37999, 38207, 38217, 38227, 38237, 38247, 38257, 38267, 38277, 38287, 38297, 38720, 38721, 38722, 38723, 38724, 38725, 38726, 38727, 38728, 38729, 38999, 39206, 39216, 39226, 39236, 39246, 39256, 39266, 39276, 39286, 39296, 39620, 39621, 39622, 39623, 39624, 39625, 39626, 39627, 39628, 39629, 39999, 40000]

27387 is a lucky and self number.

27387 can be written as a digit equation via

(-2 + 7) * 3 = 8 + 7

27387 stabilises after about 180 generations of Conway's Game of Life rules to a single glider, three still life blocks and a single still life ship. There is an earlier glider but it crashes into a block and disappeared.