128111009 has 8 divisors (see below), whose sum is σ = 142723560. Its totient is φ = 114178176.

The previous prime is 128110979. The next prime is 128111023. The reversal of 128111009 is 900111821.

It can be written as a sum of positive squares in 4 ways, for example, as 8427409 + 119683600 = 2903^2 + 10940^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 128111009 - 2²⁰ = 127062433 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (128111069) 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 7 ways as a sum of consecutive naturals, for example, 169532 + ... + 170285.

It is an arithmetic number, because the mean of its divisors is an integer number (17840445).

Almost surely, 2^128111009 is an apocalyptic number.

It is an amenable number.

128111009 is a deficient number, since it is larger than the sum of its proper divisors (14612551).

128111009 is a wasteful number, since it uses less digits than its factorization.

128111009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 339859.

The product of its (nonzero) digits is 144, while the sum is 23.

The square root of 128111009 is about 11318.6133868067. The cubic root of 128111009 is about 504.1140680444.

The spelling of 128111009 in words is "one hundred twenty-eight million, one hundred eleven thousand, nine".