128500 has 24 divisors (see below), whose sum is σ = 281736. Its totient is φ = 51200.

The previous prime is 128489. The next prime is 128509. The reversal of 128500 is 5821.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1764 + 126736 = 42^2 + 356^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128509) 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, 372 + ... + 628.

It is an arithmetic number, because the mean of its divisors is an integer number (11739).

128500 is a Friedman number, since it can be written as 500*(2^8+1), using all its digits and the basic arithmetic operations.

2¹²⁸⁵⁰⁰ is an apocalyptic number.

128500 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 128500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (140868).

128500 is an abundant number, since it is smaller than the sum of its proper divisors (153236).

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

128500 is a wasteful number, since it uses less digits than its factorization.

128500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 276 (or 264 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 16.

The square root of 128500 is about 358.4689665787. The cubic root of 128500 is about 50.4623776249.

It can be divided in two parts, 128 and 500, that multiplied together give a cube (64000 = 40³).

The spelling of 128500 in words is "one hundred twenty-eight thousand, five hundred".