686128 has 40 divisors (see below), whose sum is σ = 1460720. Its totient is φ = 311040.

The previous prime is 686117. The next prime is 686131. The reversal of 686128 is 821686.

It is a self number, because there is not a number n which added to its sum of digits gives 686128.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11218 + ... + 11278.

It is an arithmetic number, because the mean of its divisors is an integer number (36518).

2⁶⁸⁶¹²⁸ 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 686128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (730360).

686128 is an abundant number, since it is smaller than the sum of its proper divisors (774592).

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

686128 is a wasteful number, since it uses less digits than its factorization.

686128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125 (or 119 counting only the distinct ones).

The product of its digits is 4608, while the sum is 31.

The square root of 686128 is about 828.3284372759. The cubic root of 686128 is about 88.1999585221.

It can be divided in two parts, 6861 and 28, that added together give a square (6889 = 83²).

The spelling of 686128 in words is "six hundred eighty-six thousand, one hundred twenty-eight".