686423556 has 216 divisors, whose sum is σ = 2235182040. Its totient is φ = 175924224.

The previous prime is 686423539. The next prime is 686423587. The reversal of 686423556 is 655324686.

686423556 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 245423556 + 441000000 = 15666^2 + 21000^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 848080 + ... + 848888.

It is an arithmetic number, because the mean of its divisors is an integer number (10348065).

Almost surely, 2^686423556 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 686423556, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1117591020).

686423556 is an abundant number, since it is smaller than the sum of its proper divisors (1548758484).

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

686423556 is a wasteful number, since it uses less digits than its factorization.

686423556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 883 (or 871 counting only the distinct ones).

The product of its digits is 1036800, while the sum is 45.

The square root of 686423556 is about 26199.6861813267. The cubic root of 686423556 is about 882.1262102081.

The spelling of 686423556 in words is "six hundred eighty-six million, four hundred twenty-three thousand, five hundred fifty-six".