128634178791 has 4 divisors (see below), whose sum is σ = 171512238392. Its totient is φ = 85756119192.

The previous prime is 128634178679. The next prime is 128634178807. The reversal of 128634178791 is 197871436821.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 197871436821 = 3 ⋅65957145607.

It is not a de Polignac number, because 128634178791 - 2⁹ = 128634178279 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128634178391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21439029796 + ... + 21439029801.

It is an arithmetic number, because the mean of its divisors is an integer number (42878059598).

Almost surely, 2^128634178791 is an apocalyptic number.

128634178791 is a deficient number, since it is larger than the sum of its proper divisors (42878059601).

128634178791 is an equidigital number, since it uses as much as digits as its factorization.

128634178791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42878059600.

The product of its digits is 4064256, while the sum is 57.

The spelling of 128634178791 in words is "one hundred twenty-eight billion, six hundred thirty-four million, one hundred seventy-eight thousand, seven hundred ninety-one".