128161865 has 32 divisors (see below), whose sum is σ = 175875840. Its totient is φ = 88932096.

The previous prime is 128161849. The next prime is 128161867. The reversal of 128161865 is 568161821.

It is a cyclic number.

It is not a de Polignac number, because 128161865 - 2⁴ = 128161849 is a prime.

It is not an unprimeable number, because it can be changed into a prime (128161867) 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 31 ways as a sum of consecutive naturals, for example, 87479 + ... + 88931.

It is an arithmetic number, because the mean of its divisors is an integer number (5496120).

Almost surely, 2^128161865 is an apocalyptic number.

It is an amenable number.

128161865 is a deficient number, since it is larger than the sum of its proper divisors (47713975).

128161865 is a wasteful number, since it uses less digits than its factorization.

128161865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1553.

The product of its digits is 23040, while the sum is 38.

The square root of 128161865 is about 11320.8597288369. The cubic root of 128161865 is about 504.1807649755.

The spelling of 128161865 in words is "one hundred twenty-eight million, one hundred sixty-one thousand, eight hundred sixty-five".