129561804 has 72 divisors (see below), whose sum is σ = 341228160. Its totient is φ = 41414400.

The previous prime is 129561799. The next prime is 129561823. The reversal of 129561804 is 408165921.

129561804 is a `hidden beast` number, since 12 + 9 + 561 + 80 + 4 = 666.

It is a super-2 number, since 2×129561804² = 33572522111468832, which contains 22 as substring.

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

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 89317 + ... + 90755.

It is an arithmetic number, because the mean of its divisors is an integer number (4739280).

Almost surely, 2^129561804 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 129561804, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (170614080).

129561804 is an abundant number, since it is smaller than the sum of its proper divisors (211666356).

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

129561804 is a wasteful number, since it uses less digits than its factorization.

129561804 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1551 (or 1546 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The square root of 129561804 is about 11382.5218646836. The cubic root of 129561804 is about 506.0098786263.

The spelling of 129561804 in words is "one hundred twenty-nine million, five hundred sixty-one thousand, eight hundred four".