128391171 has 4 divisors (see below), whose sum is σ = 171188232. Its totient is φ = 85594112.

The previous prime is 128391097. The next prime is 128391173. The reversal of 128391171 is 171193821.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 171193821 = 3 ⋅57064607.

It is a cyclic number.

It is not a de Polignac number, because 128391171 - 2¹⁵ = 128358403 is a prime.

It is not an unprimeable number, because it can be changed into a prime (128391173) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21398526 + ... + 21398531.

It is an arithmetic number, because the mean of its divisors is an integer number (42797058).

Almost surely, 2^128391171 is an apocalyptic number.

128391171 is a deficient number, since it is larger than the sum of its proper divisors (42797061).

128391171 is an equidigital number, since it uses as much as digits as its factorization.

128391171 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42797060.

The product of its digits is 3024, while the sum is 33.

The square root of 128391171 is about 11330.9827905615. The cubic root of 128391171 is about 504.4812776449.

The spelling of 128391171 in words is "one hundred twenty-eight million, three hundred ninety-one thousand, one hundred seventy-one".