128765387 has 4 divisors (see below), whose sum is σ = 130579056. Its totient is φ = 126951720.

The previous prime is 128765381. The next prime is 128765407. The reversal of 128765387 is 783567821.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 783567821 = 18217 ⋅43013.

It is a cyclic number.

It is not a de Polignac number, because 128765387 - 2²⁰ = 127716811 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128765381) 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 3 ways as a sum of consecutive naturals, for example, 906728 + ... + 906869.

It is an arithmetic number, because the mean of its divisors is an integer number (32644764).

Almost surely, 2^128765387 is an apocalyptic number.

128765387 is a deficient number, since it is larger than the sum of its proper divisors (1813669).

128765387 is an equidigital number, since it uses as much as digits as its factorization.

128765387 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1813668.

The product of its digits is 564480, while the sum is 47.

The square root of 128765387 is about 11347.4837298848. The cubic root of 128765387 is about 504.9709318955.

The spelling of 128765387 in words is "one hundred twenty-eight million, seven hundred sixty-five thousand, three hundred eighty-seven".