129720320 has 56 divisors (see below), whose sum is σ = 311408064. Its totient is φ = 51871744.

The previous prime is 129720317. The next prime is 129720323. The reversal of 129720320 is 23027921.

It is an interprime number because it is at equal distance from previous prime (129720317) and next prime (129720323).

It is a super-2 number, since 2×129720320² = 33654722841804800, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 129720320.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129720323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 39377 + ... + 42543.

Almost surely, 2^129720320 is an apocalyptic number.

129720320 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 129720320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (155704032).

129720320 is an abundant number, since it is smaller than the sum of its proper divisors (181687744).

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

129720320 is an frugal number, since it uses more digits than its factorization.

129720320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3198 (or 3174 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 26.

The square root of 129720320 is about 11389.4828679796. The cubic root of 129720320 is about 506.2161584857.

The spelling of 129720320 in words is "one hundred twenty-nine million, seven hundred twenty thousand, three hundred twenty".