128809507 has 4 divisors (see below), whose sum is σ = 128865600. Its totient is φ = 128753416.

The previous prime is 128809487. The next prime is 128809511. The reversal of 128809507 is 705908821.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 705908821 = 1447 ⋅487843.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128809507 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 128809507.

It is not an unprimeable number, because it can be changed into a prime (128809517) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24448 + ... + 29245.

It is an arithmetic number, because the mean of its divisors is an integer number (32216400).

Almost surely, 2^128809507 is an apocalyptic number.

128809507 is a deficient number, since it is larger than the sum of its proper divisors (56093).

128809507 is an equidigital number, since it uses as much as digits as its factorization.

128809507 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56092.

The product of its (nonzero) digits is 40320, while the sum is 40.

The square root of 128809507 is about 11349.4276067122. The cubic root of 128809507 is about 505.0285994978.

The spelling of 128809507 in words is "one hundred twenty-eight million, eight hundred nine thousand, five hundred seven".