79840 has 24 divisors (see below), whose sum is σ = 189000. Its totient is φ = 31872.

The previous prime is 79829. The next prime is 79841. The reversal of 79840 is 4897.

It is a junction number, because it is equal to n+sod(n) for n = 79799 and 79808.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (79841) by changing a digit.

79840 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 90 + ... + 409.

It is an arithmetic number, because the mean of its divisors is an integer number (7875).

2⁷⁹⁸⁴⁰ is an apocalyptic number.

It is an amenable number.

79840 is an abundant number, since it is smaller than the sum of its proper divisors (109160).

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 (94500).

79840 is a wasteful number, since it uses less digits than its factorization.

79840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 514 (or 506 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 79840 is about 282.5597281992. The cubic root of 79840 is about 43.0599488329.

It can be divided in two parts, 798 and 40, that added together give a palindrome (838).

The spelling of 79840 in words is "seventy-nine thousand, eight hundred forty".