128428557 has 16 divisors (see below), whose sum is σ = 181985472. Its totient is φ = 80282880.

The previous prime is 128428549. The next prime is 128428561. The reversal of 128428557 is 755824821.

It is not a de Polignac number, because 128428557 - 2³ = 128428549 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128428507) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9582 + ... + 18672.

It is an arithmetic number, because the mean of its divisors is an integer number (11374092).

Almost surely, 2^128428557 is an apocalyptic number.

128428557 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

128428557 is a deficient number, since it is larger than the sum of its proper divisors (53556915).

128428557 is a wasteful number, since it uses less digits than its factorization.

128428557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9388.

The product of its digits is 179200, while the sum is 42.

The square root of 128428557 is about 11332.6323949910. The cubic root of 128428557 is about 504.5302392325.

The spelling of 128428557 in words is "one hundred twenty-eight million, four hundred twenty-eight thousand, five hundred fifty-seven".