128911 has 4 divisors (see below), whose sum is σ = 136512. Its totient is φ = 121312.

The previous prime is 128903. The next prime is 128923. The reversal of 128911 is 119821.

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

It is not a de Polignac number, because 128911 - 2³ = 128903 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128941) 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, 3775 + ... + 3808.

It is an arithmetic number, because the mean of its divisors is an integer number (34128).

2¹²⁸⁹¹¹ is an apocalyptic number.

128911 is a deficient number, since it is larger than the sum of its proper divisors (7601).

128911 is an equidigital number, since it uses as much as digits as its factorization.

128911 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7600.

The product of its digits is 144, while the sum is 22.

The square root of 128911 is about 359.0417802986. The cubic root of 128911 is about 50.5161207234.

The spelling of 128911 in words is "one hundred twenty-eight thousand, nine hundred eleven".