128929 has 4 divisors (see below), whose sum is σ = 133120. Its totient is φ = 124740.

The previous prime is 128923. The next prime is 128939. The reversal of 128929 is 929821.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 929821 = 23 ⋅40427.

It is a cyclic number.

It is not a de Polignac number, because 128929 - 2¹³ = 120737 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31), and also a Moran number because the ratio is a prime number: 4159 = 128929 / (1 + 2 + 8 + 9 + 2 + 9).

It is a Duffinian number.

128929 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 128929.

It is not an unprimeable number, because it can be changed into a prime (128923) 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, 2049 + ... + 2110.

It is an arithmetic number, because the mean of its divisors is an integer number (33280).

2¹²⁸⁹²⁹ is an apocalyptic number.

It is an amenable number.

128929 is a deficient number, since it is larger than the sum of its proper divisors (4191).

128929 is an equidigital number, since it uses as much as digits as its factorization.

128929 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4190.

The product of its digits is 2592, while the sum is 31.

The square root of 128929 is about 359.0668461443. The cubic root of 128929 is about 50.5184718231.

The spelling of 128929 in words is "one hundred twenty-eight thousand, nine hundred twenty-nine".