128643867 has 24 divisors (see below), whose sum is σ = 203247408. Its totient is φ = 77760000.

The previous prime is 128643859. The next prime is 128643877. The reversal of 128643867 is 768346821.

It is not a de Polignac number, because 128643867 - 2³ = 128643859 is a prime.

It is not an unprimeable number, because it can be changed into a prime (128643847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 41367 + ... + 44367.

It is an arithmetic number, because the mean of its divisors is an integer number (8468642).

Almost surely, 2^128643867 is an apocalyptic number.

128643867 is a deficient number, since it is larger than the sum of its proper divisors (74603541).

128643867 is a wasteful number, since it uses less digits than its factorization.

128643867 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3451 (or 3448 counting only the distinct ones).

The product of its digits is 387072, while the sum is 45.

The square root of 128643867 is about 11342.1279749437. The cubic root of 128643867 is about 504.8120295099.

The spelling of 128643867 in words is "one hundred twenty-eight million, six hundred forty-three thousand, eight hundred sixty-seven".