1123611561 has 16 divisors (see below), whose sum is σ = 1683316800. Its totient is φ = 740656224.

The previous prime is 1123611557. The next prime is 1123611581. The reversal of 1123611561 is 1651163211.

It is not a de Polignac number, because 1123611561 - 2² = 1123611557 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (1123611581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 231391 + ... + 236196.

It is an arithmetic number, because the mean of its divisors is an integer number (105207300).

Almost surely, 2^1123611561 is an apocalyptic number.

It is an amenable number.

1123611561 is a deficient number, since it is larger than the sum of its proper divisors (559705239).

1123611561 is an equidigital number, since it uses as much as digits as its factorization.

1123611561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 467685 (or 467679 counting only the distinct ones).

The product of its digits is 1080, while the sum is 27.

The square root of 1123611561 is about 33520.3156458885. The cubic root of 1123611561 is about 1039.6138732386.

Adding to 1123611561 its reverse (1651163211), we get a palindrome (2774774772).

The spelling of 1123611561 in words is "one billion, one hundred twenty-three million, six hundred eleven thousand, five hundred sixty-one".