128168091 has 48 divisors (see below), whose sum is σ = 202718880. Its totient is φ = 77760000.

The previous prime is 128168087. The next prime is 128168093. The reversal of 128168091 is 190861821.

It is not a de Polignac number, because 128168091 - 2² = 128168087 is a prime.

It is not an unprimeable number, because it can be changed into a prime (128168093) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 708021 + ... + 708201.

It is an arithmetic number, because the mean of its divisors is an integer number (4223310).

Almost surely, 2^128168091 is an apocalyptic number.

128168091 is a deficient number, since it is larger than the sum of its proper divisors (74550789).

128168091 is a wasteful number, since it uses less digits than its factorization.

128168091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 348 (or 345 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 36.

The square root of 128168091 is about 11321.1347046133. The cubic root of 128168091 is about 504.1889290749.

Subtracting from 128168091 its sum of digits (36), we obtain a triangular number (128168055 = T₁₆₀₁₀).

The spelling of 128168091 in words is "one hundred twenty-eight million, one hundred sixty-eight thousand, ninety-one".