128257939 has 2 divisors, whose sum is σ = 128257940. Its totient is φ = 128257938.

The previous prime is 128257931. The next prime is 128257973. The reversal of 128257939 is 939752821.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 128257939 - 2³ = 128257931 is a prime.

It is not a weakly prime, because it can be changed into another prime (128257931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64128969 + 64128970.

It is an arithmetic number, because the mean of its divisors is an integer number (64128970).

Almost surely, 2^128257939 is an apocalyptic number.

128257939 is a deficient number, since it is larger than the sum of its proper divisors (1).

128257939 is an equidigital number, since it uses as much as digits as its factorization.

128257939 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 272160, while the sum is 46.

The square root of 128257939 is about 11325.1021628946. The cubic root of 128257939 is about 504.3067165450.

The spelling of 128257939 in words is "one hundred twenty-eight million, two hundred fifty-seven thousand, nine hundred thirty-nine".