128991279 has 32 divisors (see below), whose sum is σ = 182640640. Its totient is φ = 80870400.

The previous prime is 128991253. The next prime is 128991299. The reversal of 128991279 is 972199821.

It is not a de Polignac number, because 128991279 - 2⁹ = 128990767 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 (128991299) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 712569 + ... + 712749.

It is an arithmetic number, because the mean of its divisors is an integer number (5707520).

Almost surely, 2^128991279 is an apocalyptic number.

128991279 is a deficient number, since it is larger than the sum of its proper divisors (53649361).

128991279 is a wasteful number, since it uses less digits than its factorization.

128991279 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 391.

The product of its digits is 163296, while the sum is 48.

The square root of 128991279 is about 11357.4327644939. The cubic root of 128991279 is about 505.2660480960.

The spelling of 128991279 in words is "one hundred twenty-eight million, nine hundred ninety-one thousand, two hundred seventy-nine".