686478 has 24 divisors (see below), whose sum is σ = 1488888. Its totient is φ = 210912.

The previous prime is 686473. The next prime is 686479. The reversal of 686478 is 874686.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a Curzon number.

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 686478.

It is not an unprimeable number, because it can be changed into a prime (686473) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 676 + ... + 1352.

It is an arithmetic number, because the mean of its divisors is an integer number (62037).

2⁶⁸⁶⁴⁷⁸ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 686478, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (744444).

686478 is an abundant number, since it is smaller than the sum of its proper divisors (802410).

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

686478 is a wasteful number, since it uses less digits than its factorization.

686478 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 708 (or 695 counting only the distinct ones).

The product of its digits is 64512, while the sum is 39.

The square root of 686478 is about 828.5396791947. The cubic root of 686478 is about 88.2149531674.

The spelling of 686478 in words is "six hundred eighty-six thousand, four hundred seventy-eight".