129128725800 has 360 divisors, whose sum is σ = 476433677610. Its totient is φ = 32407603200.

The previous prime is 129128725771. The next prime is 129128725819. The reversal of 129128725800 is 8527821921.

129128725800 is a `hidden beast` number, since 1 + 291 + 287 + 2 + 5 + 80 + 0 = 666.

It can be written as a sum of positive squares in 9 ways, for example, as 80341634916 + 48787090884 = 283446^2 + 220878^2 .

It is a tau number, because it is divible by the number of its divisors (360).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 89 ways as a sum of consecutive naturals, for example, 4668010 + ... + 4695590.

Almost surely, 2^129128725800 is an apocalyptic number.

129128725800 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 129128725800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (238216838805).

129128725800 is an abundant number, since it is smaller than the sum of its proper divisors (347304951810).

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

129128725800 is a wasteful number, since it uses less digits than its factorization.

129128725800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27643 (or 27608 counting only the distinct ones).

The product of its (nonzero) digits is 161280, while the sum is 45.

The spelling of 129128725800 in words is "one hundred twenty-nine billion, one hundred twenty-eight million, seven hundred twenty-five thousand, eight hundred".