129979728 has 120 divisors (see below), whose sum is σ = 382121376. Its totient is φ = 42768000.

The previous prime is 129979723. The next prime is 129979753. The reversal of 129979728 is 827979921.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129979721) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 392523 + ... + 392853.

Almost surely, 2^129979728 is an apocalyptic number.

129979728 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 129979728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (191060688).

129979728 is an abundant number, since it is smaller than the sum of its proper divisors (252141648).

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

129979728 is a wasteful number, since it uses less digits than its factorization.

129979728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 455 (or 437 counting only the distinct ones).

The product of its digits is 1143072, while the sum is 54.

The square root of 129979728 is about 11400.8652303235. The cubic root of 129979728 is about 506.5533687881.

The spelling of 129979728 in words is "one hundred twenty-nine million, nine hundred seventy-nine thousand, seven hundred twenty-eight".