128840 has 16 divisors (see below), whose sum is σ = 289980. Its totient is φ = 51520.

The previous prime is 128837. The next prime is 128857. The reversal of 128840 is 48821.

128840 is nontrivially palindromic in base 11.

It can be written as a sum of positive squares in 2 ways, for example, as 128164 + 676 = 358^2 + 26^2 .

128840 is a nontrivial repdigit in base 11.

It is a plaindrome in base 11.

It is a nialpdrome in base 11.

It is a zygodrome in base 11.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1571 + ... + 1650.

2¹²⁸⁸⁴⁰ is an apocalyptic number.

128840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

128840 is an abundant number, since it is smaller than the sum of its proper divisors (161140).

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

128840 is a wasteful number, since it uses less digits than its factorization.

128840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3232 (or 3228 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 23.

The square root of 128840 is about 358.9428923938. The cubic root of 128840 is about 50.5068448063.

The spelling of 128840 in words is "one hundred twenty-eight thousand, eight hundred forty".