128013689 has 4 divisors (see below), whose sum is σ = 135543924. Its totient is φ = 120483456.

The previous prime is 128013679. The next prime is 128013701. The reversal of 128013689 is 986310821.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 115197289 + 12816400 = 10733^2 + 3580^2 .

It is a cyclic number.

It is not a de Polignac number, because 128013689 - 2⁸ = 128013433 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (128013679) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3765092 + ... + 3765125.

It is an arithmetic number, because the mean of its divisors is an integer number (33885981).

Almost surely, 2^128013689 is an apocalyptic number.

It is an amenable number.

128013689 is a deficient number, since it is larger than the sum of its proper divisors (7530235).

128013689 is an equidigital number, since it uses as much as digits as its factorization.

128013689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7530234.

The product of its (nonzero) digits is 20736, while the sum is 38.

The square root of 128013689 is about 11314.3134568563. The cubic root of 128013689 is about 503.9863850043.

The spelling of 128013689 in words is "one hundred twenty-eight million, thirteen thousand, six hundred eighty-nine".