2561681047537 has 2 divisors, whose sum is σ = 2561681047538. Its totient is φ = 2561681047536.

The previous prime is 2561681047477. The next prime is 2561681047543. The reversal of 2561681047537 is 7357401861652.

2561681047537 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2541725529841 + 19955517696 = 1594279^2 + 141264^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2561681047537 is a prime.

It is not a weakly prime, because it can be changed into another prime (2561681047547) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1280840523768 + 1280840523769.

It is an arithmetic number, because the mean of its divisors is an integer number (1280840523769).

Almost surely, 2^{2561681047537} is an apocalyptic number.

It is an amenable number.

2561681047537 is a deficient number, since it is larger than the sum of its proper divisors (1).

2561681047537 is an equidigital number, since it uses as much as digits as its factorization.

2561681047537 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8467200, while the sum is 55.

The spelling of 2561681047537 in words is "two trillion, five hundred sixty-one billion, six hundred eighty-one million, forty-seven thousand, five hundred thirty-seven".