11561055551 has 12 divisors (see below), whose sum is σ = 11868610248. Its totient is φ = 11261247984.

The previous prime is 11561055509. The next prime is 11561055553. The reversal of 11561055551 is 15555016511.

It is a de Polignac number, because none of the positive numbers 2^k-11561055551 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11561055553) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 681296 + ... + 698058.

It is an arithmetic number, because the mean of its divisors is an integer number (989050854).

Almost surely, 2^11561055551 is an apocalyptic number.

11561055551 is a deficient number, since it is larger than the sum of its proper divisors (307554697).

11561055551 is an equidigital number, since it uses as much as digits as its factorization.

11561055551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17222 (or 17179 counting only the distinct ones).

The product of its (nonzero) digits is 18750, while the sum is 35.

The spelling of 11561055551 in words is "eleven billion, five hundred sixty-one million, fifty-five thousand, five hundred fifty-one".