2561188161 has 32 divisors (see below), whose sum is σ = 4099534848. Its totient is φ = 1390593600.

The previous prime is 2561188141. The next prime is 2561188213. The reversal of 2561188161 is 1618811652.

It is not a de Polignac number, because 2561188161 - 2⁵ = 2561188129 is a prime.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2561188121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 55375 + ... + 90491.

It is an arithmetic number, because the mean of its divisors is an integer number (128110464).

Almost surely, 2^2561188161 is an apocalyptic number.

2561188161 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2561188161 is a deficient number, since it is larger than the sum of its proper divisors (1538346687).

2561188161 is a wasteful number, since it uses less digits than its factorization.

2561188161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35301.

The product of its digits is 23040, while the sum is 39.

The square root of 2561188161 is about 50608.1827474570. The cubic root of 2561188161 is about 1368.1923628087.

The spelling of 2561188161 in words is "two billion, five hundred sixty-one million, one hundred eighty-eight thousand, one hundred sixty-one".