128669305 has 4 divisors (see below), whose sum is σ = 154403172. Its totient is φ = 102935440.

The previous prime is 128669297. The next prime is 128669309. The reversal of 128669305 is 503966821.

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 92525161 + 36144144 = 9619^2 + 6012^2 .

It is not a de Polignac number, because 128669305 - 2³ = 128669297 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128669309) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12866926 + ... + 12866935.

It is an arithmetic number, because the mean of its divisors is an integer number (38600793).

Almost surely, 2^128669305 is an apocalyptic number.

It is an amenable number.

128669305 is a deficient number, since it is larger than the sum of its proper divisors (25733867).

128669305 is an equidigital number, since it uses as much as digits as its factorization.

128669305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25733866.

The product of its (nonzero) digits is 77760, while the sum is 40.

The square root of 128669305 is about 11343.2493140193. The cubic root of 128669305 is about 504.8453011105.

The spelling of 128669305 in words is "one hundred twenty-eight million, six hundred sixty-nine thousand, three hundred five".