2561113561 has 4 divisors (see below), whose sum is σ = 2593532800. Its totient is φ = 2528694324.

The previous prime is 2561113559. The next prime is 2561113589. The reversal of 2561113561 is 1653111652.

It is a happy number.

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.

It is a cyclic number.

It is not a de Polignac number, because 2561113561 - 2¹ = 2561113559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2561113501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16209501 + ... + 16209658.

It is an arithmetic number, because the mean of its divisors is an integer number (648383200).

Almost surely, 2^2561113561 is an apocalyptic number.

It is an amenable number.

2561113561 is a deficient number, since it is larger than the sum of its proper divisors (32419239).

2561113561 is an equidigital number, since it uses as much as digits as its factorization.

2561113561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32419238.

The product of its digits is 5400, while the sum is 31.

The square root of 2561113561 is about 50607.4457071289. The cubic root of 2561113561 is about 1368.1790788516.

The spelling of 2561113561 in words is "two billion, five hundred sixty-one million, one hundred thirteen thousand, five hundred sixty-one".