686816 has 36 divisors (see below), whose sum is σ = 1475712. Its totient is φ = 314496.

The previous prime is 686801. The next prime is 686837. The reversal of 686816 is 618686.

686816 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an Ulam number.

It is a congruent number.

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, 5345 + ... + 5471.

It is an arithmetic number, because the mean of its divisors is an integer number (40992).

2⁶⁸⁶⁸¹⁶ 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 686816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (737856).

686816 is an abundant number, since it is smaller than the sum of its proper divisors (788896).

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

686816 is a wasteful number, since it uses less digits than its factorization.

686816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 163 (or 142 counting only the distinct ones).

The product of its digits is 13824, while the sum is 35.

The square root of 686816 is about 828.7436274265. The cubic root of 686816 is about 88.2294288737.

The spelling of 686816 in words is "six hundred eighty-six thousand, eight hundred sixteen".