129783728 has 20 divisors (see below), whose sum is σ = 254641440. Its totient is φ = 64069824.

The previous prime is 129783727. The next prime is 129783739. The reversal of 129783728 is 827387921.

It is a Smith number, since the sum of its digits (47) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (129783727) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 50075 + ... + 52602.

It is an arithmetic number, because the mean of its divisors is an integer number (12732072).

Almost surely, 2^129783728 is an apocalyptic number.

It is an amenable number.

129783728 is a deficient number, since it is larger than the sum of its proper divisors (124857712).

129783728 is a wasteful number, since it uses less digits than its factorization.

129783728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102764 (or 102758 counting only the distinct ones).

The product of its digits is 338688, while the sum is 47.

The square root of 129783728 is about 11392.2661485764. The cubic root of 129783728 is about 506.2986254569.

The spelling of 129783728 in words is "one hundred twenty-nine million, seven hundred eighty-three thousand, seven hundred twenty-eight".