128979686 has 16 divisors (see below), whose sum is σ = 216206928. Its totient is φ = 57196800.

The previous prime is 128979677. The next prime is 128979689. The reversal of 128979686 is 686979821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128979689) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 70595 + ... + 72398.

It is an arithmetic number, because the mean of its divisors is an integer number (13512933).

Almost surely, 2^128979686 is an apocalyptic number.

128979686 is a deficient number, since it is larger than the sum of its proper divisors (87227242).

128979686 is a wasteful number, since it uses less digits than its factorization.

128979686 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143047.

The product of its digits is 2612736, while the sum is 56.

The square root of 128979686 is about 11356.9223824062. The cubic root of 128979686 is about 505.2509108329.

The spelling of 128979686 in words is "one hundred twenty-eight million, nine hundred seventy-nine thousand, six hundred eighty-six".