686789 has 2 divisors, whose sum is σ = 686790. Its totient is φ = 686788.

The previous prime is 686773. The next prime is 686797. The reversal of 686789 is 987686.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 574564 + 112225 = 758^2 + 335^2 .

It is a cyclic number.

It is not a de Polignac number, because 686789 - 2⁴ = 686773 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (686729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343394 + 343395.

It is an arithmetic number, because the mean of its divisors is an integer number (343395).

2⁶⁸⁶⁷⁸⁹ is an apocalyptic number.

It is an amenable number.

686789 is a deficient number, since it is larger than the sum of its proper divisors (1).

686789 is an equidigital number, since it uses as much as digits as its factorization.

686789 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 145152, while the sum is 44.

The square root of 686789 is about 828.7273375484. The cubic root of 686789 is about 88.2282727049.

The spelling of 686789 in words is "six hundred eighty-six thousand, seven hundred eighty-nine".