2561239 has 2 divisors, whose sum is σ = 2561240. Its totient is φ = 2561238.

The previous prime is 2561233. The next prime is 2561261. The reversal of 2561239 is 9321652.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 2561239 - 2³ = 2561231 is a prime.

2561239 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2561231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1280619 + 1280620.

It is an arithmetic number, because the mean of its divisors is an integer number (1280620).

2^2561239 is an apocalyptic number.

2561239 is a deficient number, since it is larger than the sum of its proper divisors (1).

2561239 is an equidigital number, since it uses as much as digits as its factorization.

2561239 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3240, while the sum is 28.

The square root of 2561239 is about 1600.3871406632. The cubic root of 2561239 is about 136.8201415517.

It can be divided in two parts, 25612 and 39, that added together give a triangular number (25651 = T₂₂₆).

The spelling of 2561239 in words is "two million, five hundred sixty-one thousand, two hundred thirty-nine".