128681 has 8 divisors (see below), whose sum is σ = 152064. Its totient is φ = 106560.

The previous prime is 128677. The next prime is 128683. The reversal of 128681 is 186821.

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

It is a cyclic number.

It is not a de Polignac number, because 128681 - 2² = 128677 is a prime.

It is a super-2 number, since 2×128681² = 33117599522, which contains 22 as substring.

It is a Duffinian number.

It is a nialpdrome in base 11.

It is a self number, because there is not a number n which added to its sum of digits gives 128681.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 128681.

It is not an unprimeable number, because it can be changed into a prime (128683) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 80 + ... + 513.

It is an arithmetic number, because the mean of its divisors is an integer number (19008).

2¹²⁸⁶⁸¹ is an apocalyptic number.

It is an amenable number.

128681 is a deficient number, since it is larger than the sum of its proper divisors (23383).

128681 is an equidigital number, since it uses as much as digits as its factorization.

128681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 631.

The product of its digits is 768, while the sum is 26.

The square root of 128681 is about 358.7213403186. The cubic root of 128681 is about 50.4860596100.

It can be divided in two parts, 1 and 28681, that added together give a palindrome (28682).

The spelling of 128681 in words is "one hundred twenty-eight thousand, six hundred eighty-one".