689789 has 2 divisors, whose sum is σ = 689790. Its totient is φ = 689788.

The previous prime is 689779. The next prime is 689797. The reversal of 689789 is 987986.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 422500 + 267289 = 650^2 + 517^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-689789 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (689779) 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, 344894 + 344895.

It is an arithmetic number, because the mean of its divisors is an integer number (344895).

2⁶⁸⁹⁷⁸⁹ is an apocalyptic number.

It is an amenable number.

689789 is a deficient number, since it is larger than the sum of its proper divisors (1).

689789 is an equidigital number, since it uses as much as digits as its factorization.

689789 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 217728, while the sum is 47.

The square root of 689789 is about 830.5353695057. The cubic root of 689789 is about 88.3565509951.

The spelling of 689789 in words is "six hundred eighty-nine thousand, seven hundred eighty-nine".