680989 has 2 divisors, whose sum is σ = 680990. Its totient is φ = 680988.

The previous prime is 680987. The next prime is 680993. The reversal of 680989 is 989086.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 396900 + 284089 = 630^2 + 533^2 .

It is a cyclic number.

It is not a de Polignac number, because 680989 - 2¹ = 680987 is a prime.

Together with 680987, it forms a pair of twin primes.

It is an Ulam number.

680989 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (680987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340494 + 340495.

It is an arithmetic number, because the mean of its divisors is an integer number (340495).

2⁶⁸⁰⁹⁸⁹ is an apocalyptic number.

It is an amenable number.

680989 is a deficient number, since it is larger than the sum of its proper divisors (1).

680989 is an equidigital number, since it uses as much as digits as its factorization.

680989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 31104, while the sum is 40.

The square root of 680989 is about 825.2205765733. The cubic root of 680989 is about 87.9792047970.

The spelling of 680989 in words is "six hundred eighty thousand, nine hundred eighty-nine".