129115779840 has 864 divisors, whose sum is σ = 493424870400. Its totient is φ = 31959982080.

The previous prime is 129115779829. The next prime is 129115779847. The reversal of 129115779840 is 48977511921.

129115779840 is a `hidden beast` number, since 1 + 29 + 1 + 1 + 577 + 9 + 8 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (864).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a zygodrome in base 2.

It is not an unprimeable number, because it can be changed into a prime (129115779847) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 985616575 + ... + 985616705.

It is an arithmetic number, because the mean of its divisors is an integer number (571093600).

Almost surely, 2^129115779840 is an apocalyptic number.

129115779840 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 129115779840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (246712435200).

129115779840 is an abundant number, since it is smaller than the sum of its proper divisors (364309090560).

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

129115779840 is a wasteful number, since it uses less digits than its factorization.

129115779840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 278 (or 239 counting only the distinct ones).

The product of its (nonzero) digits is 1270080, while the sum is 54.

The spelling of 129115779840 in words is "one hundred twenty-nine billion, one hundred fifteen million, seven hundred seventy-nine thousand, eight hundred forty".