129931920 has 120 divisors (see below), whose sum is σ = 440491896. Its totient is φ = 34320384.

The previous prime is 129931913. The next prime is 129931933. The reversal of 129931920 is 29139921.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 3504384 + 126427536 = 1872^2 + 11244^2 .

It is a tau number, because it is divible by the number of its divisors (120).

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

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 80562 + ... + 82158.

Almost surely, 2^129931920 is an apocalyptic number.

129931920 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 129931920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (220245948).

129931920 is an abundant number, since it is smaller than the sum of its proper divisors (310559976).

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

129931920 is a wasteful number, since it uses less digits than its factorization.

129931920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1729 (or 1720 counting only the distinct ones).

The product of its (nonzero) digits is 8748, while the sum is 36.

The square root of 129931920 is about 11398.7683545197. The cubic root of 129931920 is about 506.4912558377.

The spelling of 129931920 in words is "one hundred twenty-nine million, nine hundred thirty-one thousand, nine hundred twenty".