128124809 has 8 divisors (see below), whose sum is σ = 134994240. Its totient is φ = 121268016.

The previous prime is 128124769. The next prime is 128124811. The reversal of 128124809 is 908421821.

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 128124809 - 2⁸ = 128124553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (128124889) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23507 + ... + 28439.

It is an arithmetic number, because the mean of its divisors is an integer number (16874280).

Almost surely, 2^128124809 is an apocalyptic number.

128124809 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

128124809 is a deficient number, since it is larger than the sum of its proper divisors (6869431).

128124809 is a wasteful number, since it uses less digits than its factorization.

128124809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6319.

The product of its (nonzero) digits is 9216, while the sum is 35.

The square root of 128124809 is about 11319.2229857000. Note that the first 3 decimals coincide. The cubic root of 128124809 is about 504.1321682957.

The spelling of 128124809 in words is "one hundred twenty-eight million, one hundred twenty-four thousand, eight hundred nine".