128323820091 has 4 divisors (see below), whose sum is σ = 171098426792. Its totient is φ = 85549213392.

The previous prime is 128323820071. The next prime is 128323820101. The reversal of 128323820091 is 190028323821.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 128323820091 - 2¹⁰ = 128323819067 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128323820071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21387303346 + ... + 21387303351.

It is an arithmetic number, because the mean of its divisors is an integer number (42774606698).

Almost surely, 2^128323820091 is an apocalyptic number.

128323820091 is a deficient number, since it is larger than the sum of its proper divisors (42774606701).

128323820091 is an equidigital number, since it uses as much as digits as its factorization.

128323820091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42774606700.

The product of its (nonzero) digits is 41472, while the sum is 39.

The spelling of 128323820091 in words is "one hundred twenty-eight billion, three hundred twenty-three million, eight hundred twenty thousand, ninety-one".