129409920 has 128 divisors (see below), whose sum is σ = 458388000. Its totient is φ = 34504704.

The previous prime is 129409913. The next prime is 129409963. The reversal of 129409920 is 29904921.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13536 + ... + 21024.

Almost surely, 2^129409920 is an apocalyptic number.

129409920 is a gapful number since it is divisible by the number (10) 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 129409920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (229194000).

129409920 is an abundant number, since it is smaller than the sum of its proper divisors (328978080).

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

129409920 is an equidigital number, since it uses as much as digits as its factorization.

129409920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7517 (or 7499 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 36.

The square root of 129409920 is about 11375.8481002517. The cubic root of 129409920 is about 505.8120712128.

The spelling of 129409920 in words is "one hundred twenty-nine million, four hundred nine thousand, nine hundred twenty".