686557657 has 8 divisors (see below), whose sum is σ = 695983680. Its totient is φ = 677159280.

The previous prime is 686557639. The next prime is 686557679. The reversal of 686557657 is 756755686.

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 686557657 - 2²⁷ = 552339929 is a prime.

It is a super-2 number, since 2×686557657² = 942722832770659298, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 686557598 and 686557607.

It is not an unprimeable number, because it can be changed into a prime (686557357) 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, 45819 + ... + 58927.

It is an arithmetic number, because the mean of its divisors is an integer number (86997960).

Almost surely, 2^686557657 is an apocalyptic number.

It is an amenable number.

686557657 is a deficient number, since it is larger than the sum of its proper divisors (9426023).

686557657 is a wasteful number, since it uses less digits than its factorization.

686557657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13823.

The product of its digits is 10584000, while the sum is 55.

The square root of 686557657 is about 26202.2452663889. The cubic root of 686557657 is about 882.1836510809.

The spelling of 686557657 in words is "six hundred eighty-six million, five hundred fifty-seven thousand, six hundred fifty-seven".