128440 has 48 divisors (see below), whose sum is σ = 329400. Its totient is φ = 44928.

The previous prime is 128437. The next prime is 128449. The reversal of 128440 is 44821.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is a nialpdrome in base 11.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128449) 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 11 ways as a sum of consecutive naturals, for example, 6751 + ... + 6769.

2¹²⁸⁴⁴⁰ is an apocalyptic number.

128440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 128440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (164700).

128440 is an abundant number, since it is smaller than the sum of its proper divisors (200960).

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

128440 is a wasteful number, since it uses less digits than its factorization.

128440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56 (or 39 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 19.

The square root of 128440 is about 358.3852675543. The cubic root of 128440 is about 50.4545223356.

It can be divided in two parts, 1284 and 40, that multiplied together give a triangular number (51360 = T₃₂₀).

The spelling of 128440 in words is "one hundred twenty-eight thousand, four hundred forty".