129178728 has 48 divisors (see below), whose sum is σ = 399840480. Its totient is φ = 36908064.

The previous prime is 129178727. The next prime is 129178769. The reversal of 129178728 is 827871921.

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (129178727) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 127650 + ... + 128657.

It is an arithmetic number, because the mean of its divisors is an integer number (8330010).

Almost surely, 2^129178728 is an apocalyptic number.

129178728 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

129178728 is an abundant number, since it is smaller than the sum of its proper divisors (270661752).

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

129178728 is a wasteful number, since it uses less digits than its factorization.

129178728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 256326 (or 256319 counting only the distinct ones).

The product of its digits is 112896, while the sum is 45.

The square root of 129178728 is about 11365.6820296892. The cubic root of 129178728 is about 505.5106790384.

The spelling of 129178728 in words is "one hundred twenty-nine million, one hundred seventy-eight thousand, seven hundred twenty-eight".