11561009556 has 24 divisors (see below), whose sum is σ = 27007116640. Its totient is φ = 3849180192.

The previous prime is 11561009539. The next prime is 11561009573. The reversal of 11561009556 is 65590016511.

It is an interprime number because it is at equal distance from previous prime (11561009539) and next prime (11561009573).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 550471 + ... + 571086.

Almost surely, 2^11561009556 is an apocalyptic number.

It is an amenable number.

11561009556 is an abundant number, since it is smaller than the sum of its proper divisors (15446107084).

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

11561009556 is a wasteful number, since it uses less digits than its factorization.

11561009556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1122423 (or 1122421 counting only the distinct ones).

The product of its (nonzero) digits is 40500, while the sum is 39.

The spelling of 11561009556 in words is "eleven billion, five hundred sixty-one million, nine thousand, five hundred fifty-six".