2561161 has 4 divisors (see below), whose sum is σ = 2578500. Its totient is φ = 2543824.

The previous prime is 2561159. The next prime is 2561179. The reversal of 2561161 is 1611652.

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 1394761 + 1166400 = 1181^2 + 1080^2 .

It is a cyclic number.

It is not a de Polignac number, because 2561161 - 2¹ = 2561159 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2561191) 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, 8446 + ... + 8743.

It is an arithmetic number, because the mean of its divisors is an integer number (644625).

2^2561161 is an apocalyptic number.

It is an amenable number.

2561161 is a deficient number, since it is larger than the sum of its proper divisors (17339).

2561161 is a wasteful number, since it uses less digits than its factorization.

2561161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17338.

The product of its digits is 360, while the sum is 22.

The square root of 2561161 is about 1600.3627713740. The cubic root of 2561161 is about 136.8187526303.

The spelling of 2561161 in words is "two million, five hundred sixty-one thousand, one hundred sixty-one".