686009 has 2 divisors, whose sum is σ = 686010. Its totient is φ = 686008.

The previous prime is 686003. The next prime is 686011. The reversal of 686009 is 900686.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 529984 + 156025 = 728^2 + 395^2 .

It is a cyclic number.

It is not a de Polignac number, because 686009 - 2⁸ = 685753 is a prime.

Together with 686011, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (686003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343004 + 343005.

It is an arithmetic number, because the mean of its divisors is an integer number (343005).

2⁶⁸⁶⁰⁰⁹ is an apocalyptic number.

It is an amenable number.

686009 is a deficient number, since it is larger than the sum of its proper divisors (1).

686009 is an equidigital number, since it uses as much as digits as its factorization.

686009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2592, while the sum is 29.

The square root of 686009 is about 828.2566027506. The cubic root of 686009 is about 88.1948591811.

The spelling of 686009 in words is "six hundred eighty-six thousand, nine".