129664728 has 48 divisors (see below), whose sum is σ = 358656480. Its totient is φ = 42300864.

The previous prime is 129664679. The next prime is 129664739. The reversal of 129664728 is 827466921.

It is a happy number.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 15775 + ... + 22542.

It is an arithmetic number, because the mean of its divisors is an integer number (7472010).

Almost surely, 2^129664728 is an apocalyptic number.

129664728 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

129664728 is an abundant number, since it is smaller than the sum of its proper divisors (228991752).

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

129664728 is a wasteful number, since it uses less digits than its factorization.

129664728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38376 (or 38369 counting only the distinct ones).

The product of its digits is 290304, while the sum is 45.

The square root of 129664728 is about 11387.0421093452. The cubic root of 129664728 is about 506.1438347107.

The spelling of 129664728 in words is "one hundred twenty-nine million, six hundred sixty-four thousand, seven hundred twenty-eight".