2561549 has 2 divisors, whose sum is σ = 2561550. Its totient is φ = 2561548.

The previous prime is 2561527. The next prime is 2561551. The reversal of 2561549 is 9451652.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1525225 + 1036324 = 1235^2 + 1018^2 .

It is a cyclic number.

It is not a de Polignac number, because 2561549 - 2¹² = 2557453 is a prime.

It is a Sophie Germain prime.

Together with 2561551, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2561749) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1280774 + 1280775.

It is an arithmetic number, because the mean of its divisors is an integer number (1280775).

2^2561549 is an apocalyptic number.

It is an amenable number.

2561549 is a deficient number, since it is larger than the sum of its proper divisors (1).

2561549 is an equidigital number, since it uses as much as digits as its factorization.

2561549 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10800, while the sum is 32.

The square root of 2561549 is about 1600.4839892982. The cubic root of 2561549 is about 136.8256613455.

The spelling of 2561549 in words is "two million, five hundred sixty-one thousand, five hundred forty-nine".