686872656 has 160 divisors (see below), whose sum is σ = 2062368000. Its totient is φ = 218598912.

The previous prime is 686872651. The next prime is 686872679. The reversal of 686872656 is 656278686.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686872651) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1365301 + ... + 1365803.

It is an arithmetic number, because the mean of its divisors is an integer number (12889800).

Almost surely, 2^686872656 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 686872656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1031184000).

686872656 is an abundant number, since it is smaller than the sum of its proper divisors (1375495344).

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

686872656 is a wasteful number, since it uses less digits than its factorization.

686872656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 658 (or 646 counting only the distinct ones).

The product of its digits is 5806080, while the sum is 54.

The square root of 686872656 is about 26208.2554932601. The cubic root of 686872656 is about 882.3185484571.

It can be divided in two parts, 6868 and 72656, that added together give a square (79524 = 282²).

The spelling of 686872656 in words is "six hundred eighty-six million, eight hundred seventy-two thousand, six hundred fifty-six".