2561399 has 6 divisors (see below), whose sum is σ = 2633904. Its totient is φ = 2490840.

The previous prime is 2561389. The next prime is 2561401. The reversal of 2561399 is 9931652.

It is a de Polignac number, because none of the positive numbers 2^k-2561399 is a prime.

It is a Duffinian number.

It is a plaindrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2561389) 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 5 ways as a sum of consecutive naturals, for example, 434 + ... + 2304.

It is an arithmetic number, because the mean of its divisors is an integer number (438984).

2^2561399 is an apocalyptic number.

2561399 is a deficient number, since it is larger than the sum of its proper divisors (72505).

2561399 is an equidigital number, since it uses as much as digits as its factorization.

2561399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1945 (or 1908 counting only the distinct ones).

The product of its digits is 14580, while the sum is 35.

The square root of 2561399 is about 1600.4371277873. The cubic root of 2561399 is about 136.8229905331.

The spelling of 2561399 in words is "two million, five hundred sixty-one thousand, three hundred ninety-nine".