128557979 has 16 divisors (see below), whose sum is σ = 142560000. Its totient is φ = 114959520.

The previous prime is 128557973. The next prime is 128557981. The reversal of 128557979 is 979755821.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 128557979 - 2⁴ = 128557963 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 128557979.

It is not an unprimeable number, because it can be changed into a prime (128557973) 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, 214322 + ... + 214920.

It is an arithmetic number, because the mean of its divisors is an integer number (8910000).

Almost surely, 2^128557979 is an apocalyptic number.

128557979 is a deficient number, since it is larger than the sum of its proper divisors (14002021).

128557979 is a wasteful number, since it uses less digits than its factorization.

128557979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 898.

The product of its digits is 1587600, while the sum is 53.

The square root of 128557979 is about 11338.3411044121. The cubic root of 128557979 is about 504.6996599913.

The spelling of 128557979 in words is "one hundred twenty-eight million, five hundred fifty-seven thousand, nine hundred seventy-nine".