2560661 has 2 divisors, whose sum is σ = 2560662. Its totient is φ = 2560660.

The previous prime is 2560651. The next prime is 2560669. The reversal of 2560661 is 1660652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1716100 + 844561 = 1310^2 + 919^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2560661 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a plaindrome in base 15.

It is a self number, because there is not a number n which added to its sum of digits gives 2560661.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2560669) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1280330 + 1280331.

It is an arithmetic number, because the mean of its divisors is an integer number (1280331).

2^2560661 is an apocalyptic number.

It is an amenable number.

2560661 is a deficient number, since it is larger than the sum of its proper divisors (1).

2560661 is an equidigital number, since it uses as much as digits as its factorization.

2560661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 2560661 is about 1600.2065491680. The cubic root of 2560661 is about 136.8098486178.

Subtracting from 2560661 its reverse (1660652), we obtain a palindrome (900009).

The spelling of 2560661 in words is "two million, five hundred sixty thousand, six hundred sixty-one".