128906909 has 2 divisors, whose sum is σ = 128906910. Its totient is φ = 128906908.

The previous prime is 128906879. The next prime is 128906923. The reversal of 128906909 is 909609821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 115562500 + 13344409 = 10750^2 + 3653^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128906909 is a prime.

It is a Sophie Germain 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 128906909.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128906929) 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 as a sum of consecutive naturals, namely, 64453454 + 64453455.

It is an arithmetic number, because the mean of its divisors is an integer number (64453455).

Almost surely, 2^128906909 is an apocalyptic number.

It is an amenable number.

128906909 is a deficient number, since it is larger than the sum of its proper divisors (1).

128906909 is an equidigital number, since it uses as much as digits as its factorization.

128906909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 69984, while the sum is 44.

The square root of 128906909 is about 11353.7178492334. The cubic root of 128906909 is about 505.1558634013.

The spelling of 128906909 in words is "one hundred twenty-eight million, nine hundred six thousand, nine hundred nine".