680909 has 4 divisors (see below), whose sum is σ = 685404. Its totient is φ = 676416.

The previous prime is 680881. The next prime is 680917. The reversal of 680909 is 909086.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 909086 = 2 ⋅454543.

It can be written as a sum of positive squares in 2 ways, for example, as 75625 + 605284 = 275^2 + 778^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-680909 is a prime.

It is a Duffinian number.

680909 is a modest number, since divided by 909 gives 68 as remainder.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 680909.

It is not an unprimeable number, because it can be changed into a prime (680929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2012 + ... + 2325.

It is an arithmetic number, because the mean of its divisors is an integer number (171351).

2⁶⁸⁰⁹⁰⁹ is an apocalyptic number.

It is an amenable number.

680909 is a deficient number, since it is larger than the sum of its proper divisors (4495).

680909 is a wasteful number, since it uses less digits than its factorization.

680909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4494.

The product of its (nonzero) digits is 3888, while the sum is 32.

The square root of 680909 is about 825.1721032609. The cubic root of 680909 is about 87.9757595079.

The spelling of 680909 in words is "six hundred eighty thousand, nine hundred nine".