129521196 has 72 divisors (see below), whose sum is σ = 376215840. Its totient is φ = 36804096.

The previous prime is 129521191. The next prime is 129521209. The reversal of 129521196 is 691125921.

129521196 is a `hidden beast` number, since 129 + 521 + 1 + 9 + 6 = 666.

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

It is a self number, because there is not a number n which added to its sum of digits gives 129521196.

It is not an unprimeable number, because it can be changed into a prime (129521191) 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, 48340 + ... + 50948.

It is an arithmetic number, because the mean of its divisors is an integer number (5225220).

Almost surely, 2^129521196 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 129521196, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (188107920).

129521196 is an abundant number, since it is smaller than the sum of its proper divisors (246694644).

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

129521196 is a wasteful number, since it uses less digits than its factorization.

129521196 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2823 (or 2818 counting only the distinct ones).

The product of its digits is 9720, while the sum is 36.

The square root of 129521196 is about 11380.7379374099. The cubic root of 129521196 is about 505.9570076009.

The spelling of 129521196 in words is "one hundred twenty-nine million, five hundred twenty-one thousand, one hundred ninety-six".