129645720 has 96 divisors (see below), whose sum is σ = 434977920. Its totient is φ = 33454080.

The previous prime is 129645713. The next prime is 129645727. The reversal of 129645720 is 27546921.

129645720 is a `hidden beast` number, since 1 + 2 + 9 + 645 + 7 + 2 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (129645713) and next prime (129645727).

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 (129645727) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5352 + ... + 16968.

It is an arithmetic number, because the mean of its divisors is an integer number (4531020).

Almost surely, 2^129645720 is an apocalyptic number.

129645720 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 129645720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (217488960).

129645720 is an abundant number, since it is smaller than the sum of its proper divisors (305332200).

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

129645720 is a wasteful number, since it uses less digits than its factorization.

129645720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11665 (or 11658 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 36.

The square root of 129645720 is about 11386.2074458531. The cubic root of 129645720 is about 506.1191010449.

The spelling of 129645720 in words is "one hundred twenty-nine million, six hundred forty-five thousand, seven hundred twenty".