128307689 has 2 divisors, whose sum is σ = 128307690. Its totient is φ = 128307688.

The previous prime is 128307679. The next prime is 128307709. The reversal of 128307689 is 986703821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 119355625 + 8952064 = 10925^2 + 2992^2 .

It is an emirp because it is prime and its reverse (986703821) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 128307689 - 2²⁰ = 127259113 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (128307679) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64153844 + 64153845.

It is an arithmetic number, because the mean of its divisors is an integer number (64153845).

Almost surely, 2^128307689 is an apocalyptic number.

It is an amenable number.

128307689 is a deficient number, since it is larger than the sum of its proper divisors (1).

128307689 is an equidigital number, since it uses as much as digits as its factorization.

128307689 is an evil number, because the sum of its binary digits is even.

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

The square root of 128307689 is about 11327.2983981177. The cubic root of 128307689 is about 504.3719133302.

The spelling of 128307689 in words is "one hundred twenty-eight million, three hundred seven thousand, six hundred eighty-nine".