128020 has 24 divisors (see below), whose sum is σ = 277704. Its totient is φ = 49536.

The previous prime is 127997. The next prime is 128021. The reversal of 128020 is 20821.

128020 = T₆₄ + T₆₅ + ... + T₁₀₀.

It can be written as a sum of positive squares in 4 ways, for example, as 64516 + 63504 = 254^2 + 252^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128021) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 654 + ... + 826.

It is an arithmetic number, because the mean of its divisors is an integer number (11571).

128020 is a Friedman number, since it can be written as 20*(80^2+1), using all its digits and the basic arithmetic operations.

2¹²⁸⁰²⁰ is an apocalyptic number.

128020 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 128020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (138852).

128020 is an abundant number, since it is smaller than the sum of its proper divisors (149684).

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

128020 is a wasteful number, since it uses less digits than its factorization.

128020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 219 (or 217 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 128020 is about 357.7988261579. The cubic root of 128020 is about 50.3994666946.

Adding to 128020 its reverse (20821), we get a palindrome (148841).

It can be divided in two parts, 1280 and 20, that multiplied together give a square (25600 = 160²).

The spelling of 128020 in words is "one hundred twenty-eight thousand, twenty".