7997

7997 is a natural number that follows 7996 and precedes 7998. It is a four-digit palindromic number in base 10, since its digits read the same forward and backward (7, 9, 9, 7).

A notable arithmetic property is that every even-digit palindrome is divisible by 11; applying this rule shows that 7997 is divisible by 11, with 7997 ÷ 11 = 727.

The prime factorization of 7997 is 11 × 727. Here, both 11 and 727 are prime, making 7997 a semiprime. Since 727 is itself a palindrome, 7997 has a palindromic factorization as a product of palindromic primes.

The positive divisors of 7997 are 1, 11, 727, and 7997. The digit sum is 32, and the number is odd.

In mathematical contexts, 7997 is often cited as an example of an even-length palindrome that is a semiprime. It also illustrates how palindromic numbers relate to divisibility tricks, such as the 11-test used for alternating sums of digits.