129280 has 36 divisors (see below), whose sum is σ = 312732. Its totient is φ = 51200.

The previous prime is 129277. The next prime is 129281. The reversal of 129280 is 82921.

It can be written as a sum of positive squares in 2 ways, for example, as 92416 + 36864 = 304^2 + 192^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1230 + ... + 1330.

It is an arithmetic number, because the mean of its divisors is an integer number (8687).

2¹²⁹²⁸⁰ is an apocalyptic number.

129280 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 129280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (156366).

129280 is an abundant number, since it is smaller than the sum of its proper divisors (183452).

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

129280 is an equidigital number, since it uses as much as digits as its factorization.

129280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122 (or 108 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 22.

The square root of 129280 is about 359.5552808679. Note that the first 3 decimals coincide. The cubic root of 129280 is about 50.5642745945.

The spelling of 129280 in words is "one hundred twenty-nine thousand, two hundred eighty".