11561204556 has 144 divisors (see below), whose sum is σ = 32939026848. Its totient is φ = 3388262400.

The previous prime is 11561204539. The next prime is 11561204561. The reversal of 11561204556 is 65540216511.

11561204556 is a `hidden beast` number, since 1 + 1 + 561 + 2 + 0 + 45 + 56 = 666.

It is a super-2 number, since 2×11561204556² (a number of 21 digits) contains 22 as substring.

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 11561204556.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2532516 + ... + 2537076.

It is an arithmetic number, because the mean of its divisors is an integer number (228743242).

Almost surely, 2^11561204556 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 11561204556, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (16469513424).

11561204556 is an abundant number, since it is smaller than the sum of its proper divisors (21377822292).

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

11561204556 is a wasteful number, since it uses less digits than its factorization.

11561204556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4792 (or 4787 counting only the distinct ones).

The product of its (nonzero) digits is 36000, while the sum is 36.

The spelling of 11561204556 in words is "eleven billion, five hundred sixty-one million, two hundred four thousand, five hundred fifty-six".