40637

This number is a prime.

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The smallest Honaker prime p such that replacing each digit d in decimal expansion of p with d^2 yields a new number with distinct prime factors (dpf) 2, 3, 4 and 5 when done recursively four times, e.g., 40637 -> 16036949 (dpf 2); 16036949 -> 1360936811681 (dpf 3); 1360936811681 -> 1936081936641136641 (dpf 4); 1936081936641136641 -> 18193606418193636161193636161 (dpf 5). [Bajpai]