2561761 has 2 divisors, whose sum is σ = 2561762. Its totient is φ = 2561760.

The previous prime is 2561759. The next prime is 2561771. The reversal of 2561761 is 1671652.

2561761 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2421136 + 140625 = 1556^2 + 375^2 .

It is a cyclic number.

It is not a de Polignac number, because 2561761 - 2¹ = 2561759 is a prime.

It is a super-2 number, since 2×2561761² = 13125238842242, which contains 22 as substring.

Together with 2561759, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (2561731) 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 as a sum of consecutive naturals, namely, 1280880 + 1280881.

It is an arithmetic number, because the mean of its divisors is an integer number (1280881).

2^2561761 is an apocalyptic number.

It is an amenable number.

2561761 is a deficient number, since it is larger than the sum of its proper divisors (1).

2561761 is an equidigital number, since it uses as much as digits as its factorization.

2561761 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2520, while the sum is 28.

The square root of 2561761 is about 1600.5502178938. The cubic root of 2561761 is about 136.8294359157.

The spelling of 2561761 in words is "two million, five hundred sixty-one thousand, seven hundred sixty-one".