128924409 has 4 divisors (see below), whose sum is σ = 171899216. Its totient is φ = 85949604.

The previous prime is 128924399. The next prime is 128924429. The reversal of 128924409 is 904429821.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 128924409 - 2⁸ = 128924153 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128924429) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21487399 + ... + 21487404.

It is an arithmetic number, because the mean of its divisors is an integer number (42974804).

Almost surely, 2^128924409 is an apocalyptic number.

It is an amenable number.

128924409 is a deficient number, since it is larger than the sum of its proper divisors (42974807).

128924409 is an equidigital number, since it uses as much as digits as its factorization.

128924409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42974806.

The product of its (nonzero) digits is 41472, while the sum is 39.

The square root of 128924409 is about 11354.4884957448. The cubic root of 128924409 is about 505.1787218285.

The spelling of 128924409 in words is "one hundred twenty-eight million, nine hundred twenty-four thousand, four hundred nine".