128129 has 4 divisors (see below), whose sum is σ = 135684. Its totient is φ = 120576.

The previous prime is 128119. The next prime is 128147. The reversal of 128129 is 921821.

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

It can be written as a sum of positive squares in 2 ways, for example, as 78400 + 49729 = 280^2 + 223^2 .

It is a cyclic number.

It is not a de Polignac number, because 128129 - 2⁴ = 128113 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 (128119) 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, 3752 + ... + 3785.

It is an arithmetic number, because the mean of its divisors is an integer number (33921).

2¹²⁸¹²⁹ is an apocalyptic number.

It is an amenable number.

128129 is a deficient number, since it is larger than the sum of its proper divisors (7555).

128129 is an equidigital number, since it uses as much as digits as its factorization.

128129 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7554.

The product of its digits is 288, while the sum is 23.

The square root of 128129 is about 357.9511139807. The cubic root of 128129 is about 50.4137665006.

It can be divided in two parts, 12812 and 9, that added together give a palindrome (12821).

The spelling of 128129 in words is "one hundred twenty-eight thousand, one hundred twenty-nine".