686566620 has 72 divisors (see below), whose sum is σ = 2093481936. Its totient is φ = 182126592.

The previous prime is 686566597. The next prime is 686566627. The reversal of 686566620 is 26665686.

686566620 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686566627) 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, 24859 + ... + 44621.

It is an arithmetic number, because the mean of its divisors is an integer number (29076138).

Almost surely, 2^686566620 is an apocalyptic number.

686566620 is a gapful number since it is divisible by the number (60) 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 686566620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1046740968).

686566620 is an abundant number, since it is smaller than the sum of its proper divisors (1406915316).

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

686566620 is a wasteful number, since it uses less digits than its factorization.

686566620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19971 (or 19966 counting only the distinct ones).

The product of its (nonzero) digits is 622080, while the sum is 45.

The square root of 686566620 is about 26202.4163007918. The cubic root of 686566620 is about 882.1874900290.

It can be divided in two parts, 6865666 and 20, that added together give a palindrome (6865686).

The spelling of 686566620 in words is "six hundred eighty-six million, five hundred sixty-six thousand, six hundred twenty".