680681 has 2 divisors, whose sum is σ = 680682. Its totient is φ = 680680.

The previous prime is 680657. The next prime is 680707. The reversal of 680681 is 186086.

680681 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 672400 + 8281 = 820^2 + 91^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-680681 is a prime.

It is a super-2 number, since 2×680681² = 926653247522, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a nialpdrome in base 7.

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 680681.

It is not a weakly prime, because it can be changed into another prime (680611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340340 + 340341.

It is an arithmetic number, because the mean of its divisors is an integer number (340341).

2⁶⁸⁰⁶⁸¹ is an apocalyptic number.

It is an amenable number.

680681 is a deficient number, since it is larger than the sum of its proper divisors (1).

680681 is an equidigital number, since it uses as much as digits as its factorization.

680681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 680681 is about 825.0339386959. The cubic root of 680681 is about 87.9659389531.

The spelling of 680681 in words is "six hundred eighty thousand, six hundred eighty-one".