686736 has 60 divisors (see below), whose sum is σ = 2031120. Its totient is φ = 216000.

The previous prime is 686731. The next prime is 686737. The reversal of 686736 is 637686.

It is a happy number.

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

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 686736.

It is not an unprimeable number, because it can be changed into a prime (686731) by changing a digit.

686736 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2611 + ... + 2861.

It is an arithmetic number, because the mean of its divisors is an integer number (33852).

2⁶⁸⁶⁷³⁶ 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 686736, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1015560).

686736 is an abundant number, since it is smaller than the sum of its proper divisors (1344384).

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

686736 is a wasteful number, since it uses less digits than its factorization.

686736 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 284 (or 275 counting only the distinct ones).

The product of its digits is 36288, while the sum is 36.

The square root of 686736 is about 828.6953601897. The cubic root of 686736 is about 88.2260031001.

It can be divided in two parts, 6867 and 36, that added together give a triangular number (6903 = T₁₁₇).

The spelling of 686736 in words is "six hundred eighty-six thousand, seven hundred thirty-six".