7979 has 4 divisors (see below), whose sum is σ = 8160. Its totient is φ = 7800.

The previous prime is 7963. The next prime is 7993. The reversal of 7979 is 9797.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9797 = 97 ⋅101.

It is a cyclic number.

It is not a de Polignac number, because 7979 - 2⁴ = 7963 is a prime.

It is an Ulam number.

It is a Duffinian number.

7979 is an undulating number in base 10.

It is a plaindrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (7919) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 29 + ... + 129.

It is an arithmetic number, because the mean of its divisors is an integer number (2040).

2⁷⁹⁷⁹ is an apocalyptic number.

7979 is a gapful number since it is divisible by the number (79) formed by its first and last digit.

7979 is a deficient number, since it is larger than the sum of its proper divisors (181).

7979 is a wasteful number, since it uses less digits than its factorization.

7979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 180.

The product of its digits is 3969, while the sum is 32.

The square root of 7979 is about 89.3252483904. The cubic root of 7979 is about 19.9824846651.

The spelling of 7979 in words is "seven thousand, nine hundred seventy-nine".