128811 has 4 divisors (see below), whose sum is σ = 171752. Its totient is φ = 85872.

The previous prime is 128767. The next prime is 128813. The reversal of 128811 is 118821.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 118821 = 3 ⋅39607.

It is not a de Polignac number, because 128811 - 2⁶ = 128747 is a prime.

It is a D-number.

It is a Duffinian number.

It is a nialpdrome in base 11.

It is not an unprimeable number, because it can be changed into a prime (128813) 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, 21466 + ... + 21471.

It is an arithmetic number, because the mean of its divisors is an integer number (42938).

2¹²⁸⁸¹¹ is an apocalyptic number.

128811 is a deficient number, since it is larger than the sum of its proper divisors (42941).

128811 is an equidigital number, since it uses as much as digits as its factorization.

128811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42940.

The product of its digits is 128, while the sum is 21.

The square root of 128811 is about 358.9024937222. The cubic root of 128811 is about 50.5030550712.

It can be divided in two parts, 128 and 811, that added together give a palindrome (939).

The spelling of 128811 in words is "one hundred twenty-eight thousand, eight hundred eleven".