• 71 can be written using four 4's:
71 is nontrivially palindromic in base 7.
71 is an esthetic number in base 9, base 11 and base 13, because in such bases its adjacent digits differ by 1.
It is a strong prime.
71 is a truncatable prime.
It is a cyclic number.
It is a Chen prime.
71 is an undulating number in base 7.
It is a plaindrome in base 6, base 9, base 12, base 13, base 15 and base 16.
It is a nialpdrome in base 10, base 11 and base 14.
It is a congruent number.
It is a good prime.
71 is the 5-th centered heptagonal number.
71 is an equidigital number, since it uses as much as digits as its factorization.
71 is an evil number, because the sum of its binary digits is even.
The square root of 71 is about 8.4261497732. The cubic root of 71 is about 4.1408177494.
Adding to 71 its reverse (17), we get a palindrome (88).