128039111 has 4 divisors (see below), whose sum is σ = 128122800. Its totient is φ = 127955424.

The previous prime is 128039071. The next prime is 128039113. The reversal of 128039111 is 111930821.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128039111 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 (128039113) 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, 39506 + ... + 42623.

It is an arithmetic number, because the mean of its divisors is an integer number (32030700).

Almost surely, 2^128039111 is an apocalyptic number.

128039111 is a deficient number, since it is larger than the sum of its proper divisors (83689).

128039111 is an equidigital number, since it uses as much as digits as its factorization.

128039111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83688.

The product of its (nonzero) digits is 432, while the sum is 26.

The square root of 128039111 is about 11315.4368453012. The cubic root of 128039111 is about 504.0197447018.

Adding to 128039111 its reverse (111930821), we get a palindrome (239969932).

The spelling of 128039111 in words is "one hundred twenty-eight million, thirty-nine thousand, one hundred eleven".