128991267 has 6 divisors (see below), whose sum is σ = 186320732. Its totient is φ = 85994172.

The previous prime is 128991253. The next prime is 128991299. The reversal of 128991267 is 762199821.

It is not a de Polignac number, because 128991267 - 2⁴ = 128991251 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128991227) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 7166173 + ... + 7166190.

Almost surely, 2^128991267 is an apocalyptic number.

128991267 is a deficient number, since it is larger than the sum of its proper divisors (57329465).

128991267 is a wasteful number, since it uses less digits than its factorization.

128991267 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14332369 (or 14332366 counting only the distinct ones).

The product of its digits is 108864, while the sum is 45.

The square root of 128991267 is about 11357.4322362055. The cubic root of 128991267 is about 505.2660324278.

The spelling of 128991267 in words is "one hundred twenty-eight million, nine hundred ninety-one thousand, two hundred sixty-seven".