128672881 has 4 divisors (see below), whose sum is σ = 136241892. Its totient is φ = 121103872.

The previous prime is 128672857. The next prime is 128672893. The reversal of 128672881 is 188276821.

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

It can be written as a sum of positive squares in 2 ways, for example, as 115777600 + 12895281 = 10760^2 + 3591^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128672881 is a prime.

It is a super-2 number, since 2×128672881² = 33113420609680322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128672821) 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, 3784480 + ... + 3784513.

It is an arithmetic number, because the mean of its divisors is an integer number (34060473).

Almost surely, 2^128672881 is an apocalyptic number.

It is an amenable number.

128672881 is a deficient number, since it is larger than the sum of its proper divisors (7569011).

128672881 is an equidigital number, since it uses as much as digits as its factorization.

128672881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7569010.

The product of its digits is 86016, while the sum is 43.

The square root of 128672881 is about 11343.4069397161. The cubic root of 128672881 is about 504.8499779837.

The spelling of 128672881 in words is "one hundred twenty-eight million, six hundred seventy-two thousand, eight hundred eighty-one".