128666089 has 4 divisors (see below), whose sum is σ = 132816640. Its totient is φ = 124515540.

The previous prime is 128666039. The next prime is 128666093. The reversal of 128666089 is 980666821.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 980666821 = 709 ⋅1383169.

It is a cyclic number.

It is not a de Polignac number, because 128666089 - 2⁹ = 128665577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128666039) 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, 2075229 + ... + 2075290.

It is an arithmetic number, because the mean of its divisors is an integer number (33204160).

Almost surely, 2^128666089 is an apocalyptic number.

It is an amenable number.

128666089 is a deficient number, since it is larger than the sum of its proper divisors (4150551).

128666089 is an equidigital number, since it uses as much as digits as its factorization.

128666089 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4150550.

The product of its (nonzero) digits is 248832, while the sum is 46.

The square root of 128666089 is about 11343.1075548105. The cubic root of 128666089 is about 504.8410949894.

The spelling of 128666089 in words is "one hundred twenty-eight million, six hundred sixty-six thousand, eighty-nine".