128611191 has 4 divisors (see below), whose sum is σ = 171481592. Its totient is φ = 85740792.

The previous prime is 128611169. The next prime is 128611199. The reversal of 128611191 is 191116821.

It is a happy number.

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

It is not a de Polignac number, because 128611191 - 2⁵ = 128611159 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 (128611199) 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, 21435196 + ... + 21435201.

It is an arithmetic number, because the mean of its divisors is an integer number (42870398).

Almost surely, 2^128611191 is an apocalyptic number.

128611191 is a deficient number, since it is larger than the sum of its proper divisors (42870401).

128611191 is an equidigital number, since it uses as much as digits as its factorization.

128611191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42870400.

The product of its digits is 864, while the sum is 30.

The square root of 128611191 is about 11340.6874130275. The cubic root of 128611191 is about 504.7692845399.

The spelling of 128611191 in words is "one hundred twenty-eight million, six hundred eleven thousand, one hundred ninety-one".