686865661 has 8 divisors (see below), whose sum is σ = 718591104. Its totient is φ = 655853280.

The previous prime is 686865659. The next prime is 686865701. The reversal of 686865661 is 166568686.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 686865661 - 2¹ = 686865659 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 686865599 and 686865608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686865461) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 176295 + ... + 180148.

It is an arithmetic number, because the mean of its divisors is an integer number (89823888).

Almost surely, 2^686865661 is an apocalyptic number.

It is an amenable number.

686865661 is a deficient number, since it is larger than the sum of its proper divisors (31725443).

686865661 is a wasteful number, since it uses less digits than its factorization.

686865661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 356531.

The product of its digits is 2488320, while the sum is 52.

The square root of 686865661 is about 26208.1220426035. The cubic root of 686865661 is about 882.3155533171.

It can be divided in two parts, 68686 and 5661, that added together give a palindrome (74347).

The spelling of 686865661 in words is "six hundred eighty-six million, eight hundred sixty-five thousand, six hundred sixty-one".