128772809 has 16 divisors (see below), whose sum is σ = 144218880. Its totient is φ = 113976960.

The previous prime is 128772781. The next prime is 128772817. The reversal of 128772809 is 908277821.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128772809 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 128772809.

It is not an unprimeable number, because it can be changed into a prime (128772859) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 119927 + ... + 120995.

It is an arithmetic number, because the mean of its divisors is an integer number (9013680).

Almost surely, 2^128772809 is an apocalyptic number.

It is an amenable number.

128772809 is a deficient number, since it is larger than the sum of its proper divisors (15446071).

128772809 is a wasteful number, since it uses less digits than its factorization.

128772809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1360.

The product of its (nonzero) digits is 112896, while the sum is 44.

The square root of 128772809 is about 11347.8107580273. The cubic root of 128772809 is about 504.9806338356.

The spelling of 128772809 in words is "one hundred twenty-eight million, seven hundred seventy-two thousand, eight hundred nine".