128305391 has 2 divisors, whose sum is σ = 128305392. Its totient is φ = 128305390.

The previous prime is 128305369. The next prime is 128305393. The reversal of 128305391 is 193503821.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 128305391 - 2⁶ = 128305327 is a prime.

Together with 128305393, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128305393) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64152695 + 64152696.

It is an arithmetic number, because the mean of its divisors is an integer number (64152696).

Almost surely, 2^128305391 is an apocalyptic number.

128305391 is a deficient number, since it is larger than the sum of its proper divisors (1).

128305391 is an equidigital number, since it uses as much as digits as its factorization.

128305391 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6480, while the sum is 32.

The square root of 128305391 is about 11327.1969612963. The cubic root of 128305391 is about 504.3689021997.

The spelling of 128305391 in words is "one hundred twenty-eight million, three hundred five thousand, three hundred ninety-one".