128991066 has 8 divisors (see below), whose sum is σ = 257982144. Its totient is φ = 42997020.

The previous prime is 128991011. The next prime is 128991067. The reversal of 128991066 is 660199821.

It is a sphenic number, since it is the product of 3 distinct primes.

128991066 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (128991067) 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, 10749250 + ... + 10749261.

It is an arithmetic number, because the mean of its divisors is an integer number (32247768).

Almost surely, 2^128991066 is an apocalyptic number.

128991066 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

128991066 is a wasteful number, since it uses less digits than its factorization.

128991066 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21498516.

The product of its (nonzero) digits is 46656, while the sum is 42.

The square root of 128991066 is about 11357.4233873709. The cubic root of 128991066 is about 505.2657699849.

The spelling of 128991066 in words is "one hundred twenty-eight million, nine hundred ninety-one thousand, sixty-six".