128329581 has 12 divisors (see below), whose sum is σ = 178871168. Its totient is φ = 81832344.

The previous prime is 128329577. The next prime is 128329613. The reversal of 128329581 is 185923821.

It is not a de Polignac number, because 128329581 - 2² = 128329577 is a prime.

It is a super-2 number, since 2×128329581² = 32936962719271122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128329541) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 38845 + ... + 42018.

Almost surely, 2^128329581 is an apocalyptic number.

It is an amenable number.

128329581 is a deficient number, since it is larger than the sum of its proper divisors (50541587).

128329581 is an equidigital number, since it uses as much as digits as its factorization.

128329581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80912 (or 80889 counting only the distinct ones).

The product of its digits is 34560, while the sum is 39.

The square root of 128329581 is about 11328.2646950007. The cubic root of 128329581 is about 504.4005971970.

The spelling of 128329581 in words is "one hundred twenty-eight million, three hundred twenty-nine thousand, five hundred eighty-one".