2561949 has 24 divisors (see below), whose sum is σ = 4137952. Its totient is φ = 1574640.

The previous prime is 2561929. The next prime is 2561953. The reversal of 2561949 is 9491652.

2561949 is a `hidden beast` number, since 2 + 561 + 94 + 9 = 666.

It is not a de Polignac number, because 2561949 - 2⁷ = 2561821 is a prime.

It is an Ulam number.

2561949 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2561929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2754 + ... + 3564.

2^2561949 is an apocalyptic number.

It is an amenable number.

2561949 is a deficient number, since it is larger than the sum of its proper divisors (1576003).

2561949 is an equidigital number, since it uses as much as digits as its factorization.

2561949 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 839 (or 827 counting only the distinct ones).

The product of its digits is 19440, while the sum is 36.

The square root of 2561949 is about 1600.6089466200. The cubic root of 2561949 is about 136.8327830019.

The spelling of 2561949 in words is "two million, five hundred sixty-one thousand, nine hundred forty-nine".