978840 has 48 divisors (see below), whose sum is σ = 3182400. Its totient is φ = 260928.

The previous prime is 978839. The next prime is 978851. The reversal of 978840 is 48879.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 978795 and 978804.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 978840.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1000 + ... + 1719.

It is an arithmetic number, because the mean of its divisors is an integer number (66300).

2⁹⁷⁸⁸⁴⁰ is an apocalyptic number.

978840 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

978840 is an abundant number, since it is smaller than the sum of its proper divisors (2203560).

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

978840 is a wasteful number, since it uses less digits than its factorization.

978840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2736 (or 2729 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 36.

The square root of 978840 is about 989.3634317075. The cubic root of 978840 is about 99.2896323942.

The spelling of 978840 in words is "nine hundred seventy-eight thousand, eight hundred forty".