78840 has 64 divisors (see below), whose sum is σ = 266400. Its totient is φ = 20736.

The previous prime is 78839. The next prime is 78853. The reversal of 78840 is 4887.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a plaindrome in base 7.

It is a zygodrome in base 3 and base 7.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1044 + ... + 1116.

2⁷⁸⁸⁴⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 78840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (133200).

78840 is an abundant number, since it is smaller than the sum of its proper divisors (187560).

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

78840 is a wasteful number, since it uses less digits than its factorization.

78840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93 (or 83 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 27.

The square root of 78840 is about 280.7846149631. The cubic root of 78840 is about 42.8794169929.

It can be divided in two parts, 788 and 40, that added together give a palindrome (828).

The spelling of 78840 in words is "seventy-eight thousand, eight hundred forty".