129971520 has 336 divisors, whose sum is σ = 535106880. Its totient is φ = 29611008.

The previous prime is 129971483. The next prime is 129971521. The reversal of 129971520 is 25179921.

129971520 is a `hidden beast` number, since 129 + 9 + 7 + 1 + 520 = 666.

It is a tau number, because it is divible by the number of its divisors (336).

It is a super-2 number, since 2×129971520² = 33785192022220800, which contains 22 as substring.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129971521) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 423207 + ... + 423513.

It is an arithmetic number, because the mean of its divisors is an integer number (1592580).

Almost surely, 2^129971520 is an apocalyptic number.

129971520 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 129971520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (267553440).

129971520 is an abundant number, since it is smaller than the sum of its proper divisors (405135360).

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

129971520 is a wasteful number, since it uses less digits than its factorization.

129971520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 347 (or 324 counting only the distinct ones).

The product of its (nonzero) digits is 11340, while the sum is 36.

The square root of 129971520 is about 11400.5052519614. The cubic root of 129971520 is about 506.5427059008.

The spelling of 129971520 in words is "one hundred twenty-nine million, nine hundred seventy-one thousand, five hundred twenty".