680876809 has 4 divisors (see below), whose sum is σ = 720928404. Its totient is φ = 640825216.

The previous prime is 680876773. The next prime is 680876813. The reversal of 680876809 is 908678086.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 908678086 = 2 ⋅454339043.

It can be written as a sum of positive squares in 2 ways, for example, as 256640400 + 424236409 = 16020^2 + 20597^2 .

It is a cyclic number.

It is not a de Polignac number, because 680876809 - 2⁷ = 680876681 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (680876879) 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 in 3 ways as a sum of consecutive naturals, for example, 20025772 + ... + 20025805.

It is an arithmetic number, because the mean of its divisors is an integer number (180232101).

Almost surely, 2^680876809 is an apocalyptic number.

It is an amenable number.

680876809 is a deficient number, since it is larger than the sum of its proper divisors (40051595).

680876809 is a wasteful number, since it uses less digits than its factorization.

680876809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40051594.

The product of its (nonzero) digits is 1161216, while the sum is 52.

The square root of 680876809 is about 26093.6162499566. The cubic root of 680876809 is about 879.7437309047.

The spelling of 680876809 in words is "six hundred eighty million, eight hundred seventy-six thousand, eight hundred nine".