129680640 has 108 divisors (see below), whose sum is σ = 448721364. Its totient is φ = 34578432.

The previous prime is 129680623. The next prime is 129680651. The reversal of 129680640 is 46086921.

129680640 is a `hidden beast` number, since 1 + 2 + 9 + 6 + 8 + 0 + 640 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 80568576 + 49112064 = 8976^2 + 7008^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 129680595 and 129680604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5892 + ... + 17148.

Almost surely, 2^129680640 is an apocalyptic number.

129680640 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 129680640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (224360682).

129680640 is an abundant number, since it is smaller than the sum of its proper divisors (319040724).

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

129680640 is a wasteful number, since it uses less digits than its factorization.

129680640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11284 (or 11267 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 129680640 is about 11387.7407768178. The cubic root of 129680640 is about 506.1645379284.

The spelling of 129680640 in words is "one hundred twenty-nine million, six hundred eighty thousand, six hundred forty".