97 is: • the 25th
prime number (the largest two-digit prime number in
base 10), following
89 and preceding
101. • a
Proth prime and a
Pierpont prime as it is 3 × 25 + 1. • the eleventh member of the
Mian–Chowla sequence. • a
self number in base 10, since there is no
integer that added to its own digits, adds up to 97. • the smallest odd prime that is not a
cluster prime. • the highest two-digit number where the sum of its digits is a square. • the number of primes less than 29. • The numbers 97, 907, 9007, 90007 and 900007 are all primes, and they are all
happy primes. However, 9000007 (read as
nine million seven) is
composite and has the factorization
277 × 32491. • an
emirp with
79. • an isolated prime, since 95 and 99 are not prime. ==In other fields==