11611550561 has 4 divisors (see below), whose sum is σ = 12504746772. Its totient is φ = 10718354352.

The previous prime is 11611550551. The next prime is 11611550593. The reversal of 11611550561 is 16505511611.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7530768400 + 4080782161 = 86780^2 + 63881^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11611550561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11611550521) 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, 446598086 + ... + 446598111.

It is an arithmetic number, because the mean of its divisors is an integer number (3126186693).

Almost surely, 2^11611550561 is an apocalyptic number.

It is an amenable number.

11611550561 is a deficient number, since it is larger than the sum of its proper divisors (893196211).

11611550561 is an equidigital number, since it uses as much as digits as its factorization.

11611550561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 893196210.

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

The spelling of 11611550561 in words is "eleven billion, six hundred eleven million, five hundred fifty thousand, five hundred sixty-one".