2561651431249 has 2 divisors, whose sum is σ = 2561651431250. Its totient is φ = 2561651431248.

The previous prime is 2561651431181. The next prime is 2561651431267. The reversal of 2561651431249 is 9421341561652.

2561651431249 is digitally balanced in base 2, 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., 2514343006224 + 47308425025 = 1585668^2 + 217505^2 .

It is a cyclic number.

It is not a de Polignac number, because 2561651431249 - 2⁷ = 2561651431121 is a prime.

It is not a weakly prime, because it can be changed into another prime (2561651431289) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1280825715624 + 1280825715625.

It is an arithmetic number, because the mean of its divisors is an integer number (1280825715625).

Almost surely, 2^{2561651431249} is an apocalyptic number.

It is an amenable number.

2561651431249 is a deficient number, since it is larger than the sum of its proper divisors (1).

2561651431249 is an equidigital number, since it uses as much as digits as its factorization.

2561651431249 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1555200, while the sum is 49.

It can be divided in two parts, 2561651 and 431249, that added together give a square (2992900 = 1730²).

The spelling of 2561651431249 in words is "two trillion, five hundred sixty-one billion, six hundred fifty-one million, four hundred thirty-one thousand, two hundred forty-nine".