2561606813 has 2 divisors, whose sum is σ = 2561606814. Its totient is φ = 2561606812.

The previous prime is 2561606753. The next prime is 2561606833. The reversal of 2561606813 is 3186061652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1602961369 + 958645444 = 40037^2 + 30962^2 .

It is a cyclic number.

It is not a de Polignac number, because 2561606813 - 2⁸ = 2561606557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2561606833) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1280803406 + 1280803407.

It is an arithmetic number, because the mean of its divisors is an integer number (1280803407).

Almost surely, 2^2561606813 is an apocalyptic number.

It is an amenable number.

2561606813 is a deficient number, since it is larger than the sum of its proper divisors (1).

2561606813 is an equidigital number, since it uses as much as digits as its factorization.

2561606813 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 51840, while the sum is 38.

The square root of 2561606813 is about 50612.3187870305. The cubic root of 2561606813 is about 1368.2669070210.

The spelling of 2561606813 in words is "two billion, five hundred sixty-one million, six hundred six thousand, eight hundred thirteen".