561255645007691 has 2 divisors, whose sum is σ = 561255645007692. Its totient is φ = 561255645007690.

The previous prime is 561255645007667. The next prime is 561255645007781. The reversal of 561255645007691 is 196700546552165.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 561255645007691 - 2¹⁸ = 561255644745547 is a prime.

It is not a weakly prime, because it can be changed into another prime (561255645007991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 280627822503845 + 280627822503846.

It is an arithmetic number, because the mean of its divisors is an integer number (280627822503846).

Almost surely, 2^{561255645007691} is an apocalyptic number.

561255645007691 is a deficient number, since it is larger than the sum of its proper divisors (1).

561255645007691 is an equidigital number, since it uses as much as digits as its factorization.

561255645007691 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 68040000, while the sum is 62.

The spelling of 561255645007691 in words is "five hundred sixty-one trillion, two hundred fifty-five billion, six hundred forty-five million, seven thousand, six hundred ninety-one".