128235109 has 2 divisors, whose sum is σ = 128235110. Its totient is φ = 128235108.

The previous prime is 128235101. The next prime is 128235139. The reversal of 128235109 is 901532821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 97121025 + 31114084 = 9855^2 + 5578^2 .

It is a cyclic number.

It is not a de Polignac number, because 128235109 - 2³ = 128235101 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128235101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64117554 + 64117555.

It is an arithmetic number, because the mean of its divisors is an integer number (64117555).

Almost surely, 2^128235109 is an apocalyptic number.

It is an amenable number.

128235109 is a deficient number, since it is larger than the sum of its proper divisors (1).

128235109 is an equidigital number, since it uses as much as digits as its factorization.

128235109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4320, while the sum is 31.

The square root of 128235109 is about 11324.0941801099. The cubic root of 128235109 is about 504.2767924571.

The spelling of 128235109 in words is "one hundred twenty-eight million, two hundred thirty-five thousand, one hundred nine".