129979920 has 80 divisors (see below), whose sum is σ = 460506240. Its totient is φ = 29709312.

The previous prime is 129979879. The next prime is 129979921. The reversal of 129979920 is 29979921.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 129979920.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129979921) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37005 + ... + 40364.

It is an arithmetic number, because the mean of its divisors is an integer number (5756328).

Almost surely, 2^129979920 is an apocalyptic number.

129979920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

129979920 is an abundant number, since it is smaller than the sum of its proper divisors (330526320).

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

129979920 is a wasteful number, since it uses less digits than its factorization.

129979920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77392 (or 77386 counting only the distinct ones).

The product of its (nonzero) digits is 183708, while the sum is 48.

The square root of 129979920 is about 11400.8736507340. The cubic root of 129979920 is about 506.5536182070.

Subtracting from 129979920 its reverse (29979921), we obtain a palindrome (99999999).

The spelling of 129979920 in words is "one hundred twenty-nine million, nine hundred seventy-nine thousand, nine hundred twenty".