79909 has 4 divisors (see below), whose sum is σ = 81900. Its totient is φ = 77920.

The previous prime is 79907. The next prime is 79939. The reversal of 79909 is 90997.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 30625 + 49284 = 175^2 + 222^2 .

It is a cyclic number.

It is not a de Polignac number, because 79909 - 2¹ = 79907 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (79901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 934 + ... + 1015.

It is an arithmetic number, because the mean of its divisors is an integer number (20475).

2⁷⁹⁹⁰⁹ is an apocalyptic number.

It is an amenable number.

79909 is a deficient number, since it is larger than the sum of its proper divisors (1991).

79909 is a wasteful number, since it uses less digits than its factorization.

79909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1990.

The product of its (nonzero) digits is 5103, while the sum is 34.

The square root of 79909 is about 282.6817999094. The cubic root of 79909 is about 43.0723498056.

The spelling of 79909 in words is "seventy-nine thousand, nine hundred nine".