686140 has 72 divisors (see below), whose sum is σ = 1844640. Its totient is φ = 209664.

The previous prime is 686131. The next prime is 686141. The reversal of 686140 is 41686.

686140 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686141) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 23646 + ... + 23674.

It is an arithmetic number, because the mean of its divisors is an integer number (25620).

2⁶⁸⁶¹⁴⁰ 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 686140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (922320).

686140 is an abundant number, since it is smaller than the sum of its proper divisors (1158500).

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

686140 is a wasteful number, since it uses less digits than its factorization.

686140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71 (or 56 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 686140 is about 828.3356807478. The cubic root of 686140 is about 88.2004727086.

The spelling of 686140 in words is "six hundred eighty-six thousand, one hundred forty".