7998 has 16 divisors (see below), whose sum is σ = 16896. Its totient is φ = 2520.

The previous prime is 7993. The next prime is 8009. The reversal of 7998 is 8997.

7998 is an esthetic number in base 6, because in such base its adjacent digits differ by 1.

7998 is an undulating number in base 6.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7993) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 165 + ... + 207.

It is an arithmetic number, because the mean of its divisors is an integer number (1056).

2⁷⁹⁹⁸ is an apocalyptic number.

7998 is an abundant number, since it is smaller than the sum of its proper divisors (8898).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8448).

7998 is a wasteful number, since it uses less digits than its factorization.

7998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79.

The product of its digits is 4536, while the sum is 33.

The square root of 7998 is about 89.4315380612. The cubic root of 7998 is about 19.9983331944.

Subtracting 7998 from its reverse (8997), we obtain a palindrome (999).

Multiplying 7998 by its reverse (8997), we get a triangular number (71958006 = T₁₁₉₉₆).

The spelling of 7998 in words is "seven thousand, nine hundred ninety-eight".