689966309 has 2 divisors, whose sum is σ = 689966310. Its totient is φ = 689966308.

The previous prime is 689966279. The next prime is 689966341. The reversal of 689966309 is 903669986.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 547092100 + 142874209 = 23390^2 + 11953^2 .

It is a cyclic number.

It is not a de Polignac number, because 689966309 - 2¹² = 689962213 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (689966009) 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, 344983154 + 344983155.

It is an arithmetic number, because the mean of its divisors is an integer number (344983155).

Almost surely, 2^689966309 is an apocalyptic number.

It is an amenable number.

689966309 is a deficient number, since it is larger than the sum of its proper divisors (1).

689966309 is an equidigital number, since it uses as much as digits as its factorization.

689966309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3779136, while the sum is 56.

The square root of 689966309 is about 26267.2097680740. The cubic root of 689966309 is about 883.6412097645.

The spelling of 689966309 in words is "six hundred eighty-nine million, nine hundred sixty-six thousand, three hundred nine".