128581015 has 4 divisors (see below), whose sum is σ = 154297224. Its totient is φ = 102864808.

The previous prime is 128581007. The next prime is 128581067. The reversal of 128581015 is 510185821.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 128581015 - 2³ = 128581007 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12858097 + ... + 12858106.

It is an arithmetic number, because the mean of its divisors is an integer number (38574306).

Almost surely, 2^128581015 is an apocalyptic number.

128581015 is a deficient number, since it is larger than the sum of its proper divisors (25716209).

128581015 is an equidigital number, since it uses as much as digits as its factorization.

128581015 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25716208.

The product of its (nonzero) digits is 3200, while the sum is 31.

The square root of 128581015 is about 11339.3569041635. The cubic root of 128581015 is about 504.7298035035.

The spelling of 128581015 in words is "one hundred twenty-eight million, five hundred eighty-one thousand, fifteen".