11601155561 has 4 divisors (see below), whose sum is σ = 11638458624. Its totient is φ = 11563852500.

The previous prime is 11601155551. The next prime is 11601155591. The reversal of 11601155561 is 16555110611.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 16555110611 = 13 ⋅1273470047.

It is a cyclic number.

It is not a de Polignac number, because 11601155561 - 2³⁰ = 10527413737 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11601155551) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18651065 + ... + 18651686.

It is an arithmetic number, because the mean of its divisors is an integer number (2909614656).

Almost surely, 2^11601155561 is an apocalyptic number.

It is an amenable number.

11601155561 is a deficient number, since it is larger than the sum of its proper divisors (37303063).

11601155561 is an equidigital number, since it uses as much as digits as its factorization.

11601155561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37303062.

The product of its (nonzero) digits is 4500, while the sum is 32.

The spelling of 11601155561 in words is "eleven billion, six hundred one million, one hundred fifty-five thousand, five hundred sixty-one".