128170909 has 2 divisors, whose sum is σ = 128170910. Its totient is φ = 128170908.

The previous prime is 128170897. The next prime is 128170937. The reversal of 128170909 is 909071821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 81631225 + 46539684 = 9035^2 + 6822^2 .

It is a cyclic number.

It is not a de Polignac number, because 128170909 - 2⁵ = 128170877 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128170309) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64085454 + 64085455.

It is an arithmetic number, because the mean of its divisors is an integer number (64085455).

Almost surely, 2^128170909 is an apocalyptic number.

It is an amenable number.

128170909 is a deficient number, since it is larger than the sum of its proper divisors (1).

128170909 is an equidigital number, since it uses as much as digits as its factorization.

128170909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9072, while the sum is 37.

The square root of 128170909 is about 11321.2591614184. The cubic root of 128170909 is about 504.1926242067.

The spelling of 128170909 in words is "one hundred twenty-eight million, one hundred seventy thousand, nine hundred nine".