135211
This number is a prime.
The smallest prime p such that replacing each digit d in
decimal expansion of p with d^2 yields alternately a new
semiprime and a new sphenic number when done recursively
six times, e.g., 135211 -> 1925411 (semiprime), 1925411
-> 1814251611 (sphenic number), 1814251611 ->
16411642513611 (semiprime), 16411642513611 ->
13616113616425193611 (sphenic number), 13616113616425193611
-> 1936136119361361642518193611 (semiprime),
1936136119361361642518193611 ->
1819361936118193619361361642516418193611 (sphenic number). [Bajpai]
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