128349909 has 6 divisors (see below), whose sum is σ = 185394326. Its totient is φ = 85566600.

The previous prime is 128349901. The next prime is 128349937. The reversal of 128349909 is 909943821.

It can be written as a sum of positive squares in only one way, i.e., 113742225 + 14607684 = 10665^2 + 3822^2 .

It is not a de Polignac number, because 128349909 - 2³ = 128349901 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128349901) 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 5 ways as a sum of consecutive naturals, for example, 7130542 + ... + 7130559.

Almost surely, 2^128349909 is an apocalyptic number.

It is an amenable number.

128349909 is a deficient number, since it is larger than the sum of its proper divisors (57044417).

128349909 is a wasteful number, since it uses less digits than its factorization.

128349909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14261107 (or 14261104 counting only the distinct ones).

The product of its (nonzero) digits is 139968, while the sum is 45.

The square root of 128349909 is about 11329.1618842702. The cubic root of 128349909 is about 504.4272289211.

The spelling of 128349909 in words is "one hundred twenty-eight million, three hundred forty-nine thousand, nine hundred nine".