128193989 has 8 divisors (see below), whose sum is σ = 159826368. Its totient is φ = 99891360.

The previous prime is 128193953. The next prime is 128194049. The reversal of 128193989 is 989391821.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 128193989 - 2⁸ = 128193733 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128193929) 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, 832352 + ... + 832505.

It is an arithmetic number, because the mean of its divisors is an integer number (19978296).

Almost surely, 2^128193989 is an apocalyptic number.

It is an amenable number.

128193989 is a deficient number, since it is larger than the sum of its proper divisors (31632379).

128193989 is a wasteful number, since it uses less digits than its factorization.

128193989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1664875.

The product of its digits is 279936, while the sum is 50.

The square root of 128193989 is about 11322.2784367812. The cubic root of 128193989 is about 504.2228860590. Note that the first 3 decimals are identical.

The spelling of 128193989 in words is "one hundred twenty-eight million, one hundred ninety-three thousand, nine hundred eighty-nine".