680991 has 8 divisors (see below), whose sum is σ = 929280. Its totient is φ = 443352.

The previous prime is 680989. The next prime is 680993. The reversal of 680991 is 199086.

It is a happy number.

680991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (680989) and next prime (680993).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 680991 - 2¹ = 680989 is a prime.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (680993) 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, 2511 + ... + 2768.

It is an arithmetic number, because the mean of its divisors is an integer number (116160).

2⁶⁸⁰⁹⁹¹ is an apocalyptic number.

680991 is a deficient number, since it is larger than the sum of its proper divisors (248289).

680991 is a wasteful number, since it uses less digits than its factorization.

680991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5325.

The product of its (nonzero) digits is 3888, while the sum is 33.

The square root of 680991 is about 825.2217883696. The cubic root of 680991 is about 87.9792909258.

The spelling of 680991 in words is "six hundred eighty thousand, nine hundred ninety-one".