128649089 has 4 divisors (see below), whose sum is σ = 130461120. Its totient is φ = 126837060.

The previous prime is 128649067. The next prime is 128649113. The reversal of 128649089 is 980946821.

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: 980946821 = 18059 ⋅54319.

It is a cyclic number.

It is not a de Polignac number, because 128649089 - 2¹² = 128644993 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128649029) 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 in 3 ways as a sum of consecutive naturals, for example, 905909 + ... + 906050.

It is an arithmetic number, because the mean of its divisors is an integer number (32615280).

Almost surely, 2^128649089 is an apocalyptic number.

It is an amenable number.

128649089 is a deficient number, since it is larger than the sum of its proper divisors (1812031).

128649089 is an equidigital number, since it uses as much as digits as its factorization.

128649089 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1812030.

The product of its (nonzero) digits is 248832, while the sum is 47.

The square root of 128649089 is about 11342.3581763229. The cubic root of 128649089 is about 504.8188599761.

The spelling of 128649089 in words is "one hundred twenty-eight million, six hundred forty-nine thousand, eighty-nine".