5561611561 has 16 divisors (see below), whose sum is σ = 6338606400. Its totient is φ = 4833304000.

The previous prime is 5561611511. The next prime is 5561611597. The reversal of 5561611561 is 1651161655.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-5561611561 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 5561611561.

It is not an unprimeable number, because it can be changed into a prime (5561611511) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 54091 + ... + 118528.

It is an arithmetic number, because the mean of its divisors is an integer number (396162900).

Almost surely, 2^5561611561 is an apocalyptic number.

It is an amenable number.

5561611561 is a deficient number, since it is larger than the sum of its proper divisors (776994839).

5561611561 is a wasteful number, since it uses less digits than its factorization.

5561611561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 172760.

The product of its digits is 27000, while the sum is 37.

The square root of 5561611561 is about 74576.2131044477. The cubic root of 5561611561 is about 1771.7409282146.

It can be divided in two parts, 55 and 61611561, that added together give a palindrome (61611616).

The spelling of 5561611561 in words is "five billion, five hundred sixty-one million, six hundred eleven thousand, five hundred sixty-one".