688606489 has 2 divisors, whose sum is σ = 688606490. Its totient is φ = 688606488.

The previous prime is 688606487. The next prime is 688606507. The reversal of 688606489 is 984606886.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 658794889 + 29811600 = 25667^2 + 5460^2 .

It is a cyclic number.

It is not a de Polignac number, because 688606489 - 2¹ = 688606487 is a prime.

Together with 688606487, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (688606483) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344303244 + 344303245.

It is an arithmetic number, because the mean of its divisors is an integer number (344303245).

Almost surely, 2^688606489 is an apocalyptic number.

It is an amenable number.

688606489 is a deficient number, since it is larger than the sum of its proper divisors (1).

688606489 is an equidigital number, since it uses as much as digits as its factorization.

688606489 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3981312, while the sum is 55.

The square root of 688606489 is about 26241.3126386620. The cubic root of 688606489 is about 883.0603199316.

The spelling of 688606489 in words is "six hundred eighty-eight million, six hundred six thousand, four hundred eighty-nine".