678816 has 36 divisors (see below), whose sum is σ = 1931202. Its totient is φ = 226176.

The previous prime is 678809. The next prime is 678823. The reversal of 678816 is 618876.

It is an interprime number because it is at equal distance from previous prime (678809) and next prime (678823).

It can be written as a sum of positive squares in only one way, i.e., 646416 + 32400 = 804^2 + 180^2 .

It is a tau number, because it is divible by the number of its divisors (36).

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

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 891 + ... + 1466.

2⁶⁷⁸⁸¹⁶ is an apocalyptic number.

It is an amenable number.

678816 is an abundant number, since it is smaller than the sum of its proper divisors (1252386).

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

678816 is a wasteful number, since it uses less digits than its factorization.

678816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2373 (or 2362 counting only the distinct ones).

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

The square root of 678816 is about 823.9029069010. The cubic root of 678816 is about 87.8855260835.

The spelling of 678816 in words is "six hundred seventy-eight thousand, eight hundred sixteen".