128243409 has 32 divisors (see below), whose sum is σ = 199186176. Its totient is φ = 71884800.

The previous prime is 128243389. The next prime is 128243419. The reversal of 128243409 is 904342821.

It is not a de Polignac number, because 128243409 - 2⁷ = 128243281 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 128243409.

It is not an unprimeable number, because it can be changed into a prime (128243419) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 319609 + ... + 320009.

It is an arithmetic number, because the mean of its divisors is an integer number (6224568).

Almost surely, 2^128243409 is an apocalyptic number.

It is an amenable number.

128243409 is a deficient number, since it is larger than the sum of its proper divisors (70942767).

128243409 is a wasteful number, since it uses less digits than its factorization.

128243409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 665.

The product of its (nonzero) digits is 13824, while the sum is 33.

The square root of 128243409 is about 11324.4606494084. The cubic root of 128243409 is about 504.2876719713.

The spelling of 128243409 in words is "one hundred twenty-eight million, two hundred forty-three thousand, four hundred nine".