129728280 has 128 divisors (see below), whose sum is σ = 443128320. Its totient is φ = 30074880.

The previous prime is 129728279. The next prime is 129728317. The reversal of 129728280 is 82827921.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 28224 + ... + 32496.

It is an arithmetic number, because the mean of its divisors is an integer number (3461940).

Almost surely, 2^129728280 is an apocalyptic number.

129728280 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 129728280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (221564160).

129728280 is an abundant number, since it is smaller than the sum of its proper divisors (313400040).

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

129728280 is a wasteful number, since it uses less digits than its factorization.

129728280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4321 (or 4317 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 39.

The square root of 129728280 is about 11389.8323078086. The cubic root of 129728280 is about 506.2265125515.

The spelling of 129728280 in words is "one hundred twenty-nine million, seven hundred twenty-eight thousand, two hundred eighty".