686684856 has 96 divisors (see below), whose sum is σ = 2028049920. Its totient is φ = 192067200.

The previous prime is 686684797. The next prime is 686684857. The reversal of 686684856 is 658486686.

It is a junction number, because it is equal to n+sod(n) for n = 686684796 and 686684805.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686684857) 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, 36921 + ... + 52311.

It is an arithmetic number, because the mean of its divisors is an integer number (21125520).

Almost surely, 2^686684856 is an apocalyptic number.

686684856 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 686684856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1014024960).

686684856 is an abundant number, since it is smaller than the sum of its proper divisors (1341365064).

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

686684856 is a wasteful number, since it uses less digits than its factorization.

686684856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15437 (or 15420 counting only the distinct ones).

The product of its digits is 13271040, while the sum is 57.

The square root of 686684856 is about 26204.6724077978. The cubic root of 686684856 is about 882.2381286366.

The spelling of 686684856 in words is "six hundred eighty-six million, six hundred eighty-four thousand, eight hundred fifty-six".