129187796556 has 576 divisors, whose sum is σ = 404522926080. Its totient is φ = 31757806080.

The previous prime is 129187796503. The next prime is 129187796557. The reversal of 129187796556 is 655697781921.

It is a super-2 number, since 2×129187796556² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (129187796557) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 1254250401 + ... + 1254250503.

Almost surely, 2^129187796556 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 129187796556, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (202261463040).

129187796556 is an abundant number, since it is smaller than the sum of its proper divisors (275335129524).

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

129187796556 is a wasteful number, since it uses less digits than its factorization.

129187796556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 314 (or 305 counting only the distinct ones).

The product of its digits is 57153600, while the sum is 66.

The spelling of 129187796556 in words is "one hundred twenty-nine billion, one hundred eighty-seven million, seven hundred ninety-six thousand, five hundred fifty-six".