129250728 has 96 divisors (see below), whose sum is σ = 384471360. Its totient is φ = 40538880.

The previous prime is 129250669. The next prime is 129250741. The reversal of 129250728 is 827052921.

129250728 is a `hidden beast` number, since 129 + 2 + 507 + 28 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 129250692 and 129250701.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 31093 + ... + 35003.

It is an arithmetic number, because the mean of its divisors is an integer number (4004910).

Almost surely, 2^129250728 is an apocalyptic number.

129250728 is a gapful number since it is divisible by the number (18) 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 129250728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (192235680).

129250728 is an abundant number, since it is smaller than the sum of its proper divisors (255220632).

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

129250728 is a wasteful number, since it uses less digits than its factorization.

129250728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3949 (or 3933 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 36.

The square root of 129250728 is about 11368.8490182604. The cubic root of 129250728 is about 505.6045799704.

The spelling of 129250728 in words is "one hundred twenty-nine million, two hundred fifty thousand, seven hundred twenty-eight".