686626686 has 64 divisors (see below), whose sum is σ = 1572816960. Its totient is φ = 221875200.

The previous prime is 686626667. The next prime is 686626691.

686626686 is a `hidden beast` number, since 6 + 8 + 6 + 626 + 6 + 8 + 6 = 666.

686626686 is nontrivially palindromic in base 10.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 800770 + ... + 801626.

It is an arithmetic number, because the mean of its divisors is an integer number (24575265).

Almost surely, 2^686626686 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 686626686, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (786408480).

686626686 is an abundant number, since it is smaller than the sum of its proper divisors (886190274).

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

686626686 is a wasteful number, since it uses less digits than its factorization.

686626686 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1306 (or 1300 counting only the distinct ones).

The product of its digits is 5971968, while the sum is 54.

The square root of 686626686 is about 26203.5624677256. The cubic root of 686626686 is about 882.2132160726.

The spelling of 686626686 in words is "six hundred eighty-six million, six hundred twenty-six thousand, six hundred eighty-six".