680665 has 4 divisors (see below), whose sum is σ = 816804. Its totient is φ = 544528.

The previous prime is 680657. The next prime is 680681. The reversal of 680665 is 566086.

680665 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 484416 + 196249 = 696^2 + 443^2 .

It is a cyclic number.

It is not a de Polignac number, because 680665 - 2³ = 680657 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 68062 + ... + 68071.

It is an arithmetic number, because the mean of its divisors is an integer number (204201).

2⁶⁸⁰⁶⁶⁵ is an apocalyptic number.

It is an amenable number.

680665 is a deficient number, since it is larger than the sum of its proper divisors (136139).

680665 is a wasteful number, since it uses less digits than its factorization.

680665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 136138.

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 680665 is about 825.0242420681. The cubic root of 680665 is about 87.9652497090.

The spelling of 680665 in words is "six hundred eighty thousand, six hundred sixty-five".