128779 has 4 divisors (see below), whose sum is σ = 147184. Its totient is φ = 110376.

The previous prime is 128767. The next prime is 128813. The reversal of 128779 is 977821.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 977821 = 13 ⋅75217.

It is not a de Polignac number, because 128779 - 2⁵ = 128747 is a prime.

It is a pancake number, because a pancake can be divided into 128779 parts by 507 straight cuts.

It is a Duffinian number.

It is a nialpdrome in base 11.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128749) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9192 + ... + 9205.

It is an arithmetic number, because the mean of its divisors is an integer number (36796).

2¹²⁸⁷⁷⁹ is an apocalyptic number.

128779 is a deficient number, since it is larger than the sum of its proper divisors (18405).

128779 is an equidigital number, since it uses as much as digits as its factorization.

128779 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18404.

The product of its digits is 7056, while the sum is 34.

The square root of 128779 is about 358.8579105997. The cubic root of 128779 is about 50.4988726344.

The spelling of 128779 in words is "one hundred twenty-eight thousand, seven hundred seventy-nine".