679681 has 2 divisors, whose sum is σ = 679682. Its totient is φ = 679680.

The previous prime is 679669. The next prime is 679691. The reversal of 679681 is 186976.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 614656 + 65025 = 784^2 + 255^2 .

It is a cyclic number.

It is not a de Polignac number, because 679681 - 2⁹ = 679169 is a prime.

It is a super-2 number, since 2×679681² = 923932523522, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 679681.

It is not a weakly prime, because it can be changed into another prime (679691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 339840 + 339841.

It is an arithmetic number, because the mean of its divisors is an integer number (339841).

2⁶⁷⁹⁶⁸¹ is an apocalyptic number.

It is an amenable number.

679681 is a deficient number, since it is larger than the sum of its proper divisors (1).

679681 is an equidigital number, since it uses as much as digits as its factorization.

679681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18144, while the sum is 37.

The square root of 679681 is about 824.4276802728. The cubic root of 679681 is about 87.9228404231.

The spelling of 679681 in words is "six hundred seventy-nine thousand, six hundred eighty-one".