This number is a prime.
Metin Sariyar of Turkey found a 2971-digit palindromic prime formed from decimal expansion of π written backwards then forwards.
(2971, 7129) is the 2nd of only two pairs of primes whose both terms can be split into the same pair of complementary primes, (29, 71). The 1st such pair is (1783, 8317). [Loungrides]