129771720 has 288 divisors, whose sum is σ = 479606400. Its totient is φ = 31539456.

The previous prime is 129771713. The next prime is 129771731. The reversal of 129771720 is 27177921.

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

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 71 ways as a sum of consecutive naturals, for example, 1642641 + ... + 1642719.

It is an arithmetic number, because the mean of its divisors is an integer number (1665300).

Almost surely, 2^129771720 is an apocalyptic number.

129771720 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 129771720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (239803200).

129771720 is an abundant number, since it is smaller than the sum of its proper divisors (349834680).

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

129771720 is a wasteful number, since it uses less digits than its factorization.

129771720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131 (or 102 counting only the distinct ones).

The product of its (nonzero) digits is 12348, while the sum is 36.

The square root of 129771720 is about 11391.7391121812. The cubic root of 129771720 is about 506.2830101932.

The spelling of 129771720 in words is "one hundred twenty-nine million, seven hundred seventy-one thousand, seven hundred twenty".