128404289 has 8 divisors (see below), whose sum is σ = 139551720. Its totient is φ = 117438336.

The previous prime is 128404279. The next prime is 128404307. The reversal of 128404289 is 982404821.

It can be written as a sum of positive squares in 4 ways, for example, as 50523664 + 77880625 = 7108^2 + 8825^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 128404289 - 2¹⁶ = 128338753 is a prime.

It is a super-2 number, since 2×128404289² = 32975322867191042, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128404219) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 43892 + ... + 46725.

It is an arithmetic number, because the mean of its divisors is an integer number (17443965).

Almost surely, 2^128404289 is an apocalyptic number.

It is an amenable number.

128404289 is a deficient number, since it is larger than the sum of its proper divisors (11147431).

128404289 is a wasteful number, since it uses less digits than its factorization.

128404289 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90739.

The product of its (nonzero) digits is 36864, while the sum is 38.

The square root of 128404289 is about 11331.5616311257. The cubic root of 128404289 is about 504.4984583694.

The spelling of 128404289 in words is "one hundred twenty-eight million, four hundred four thousand, two hundred eighty-nine".