1909560056561 has 2 divisors, whose sum is σ = 1909560056562. Its totient is φ = 1909560056560.

The previous prime is 1909560056479. The next prime is 1909560056581. The reversal of 1909560056561 is 1656500659091.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1906235842225 + 3324214336 = 1380665^2 + 57656^2 .

It is an emirp because it is prime and its reverse (1656500659091) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1909560056561 - 2¹⁴ = 1909560040177 is a prime.

It is a super-2 number, since 2×1909560056561² (a number of 25 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1909560056581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 954780028280 + 954780028281.

It is an arithmetic number, because the mean of its divisors is an integer number (954780028281).

Almost surely, 2^{1909560056561} is an apocalyptic number.

It is an amenable number.

1909560056561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1909560056561 is an equidigital number, since it uses as much as digits as its factorization.

1909560056561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2187000, while the sum is 53.

The spelling of 1909560056561 in words is "one trillion, nine hundred nine billion, five hundred sixty million, fifty-six thousand, five hundred sixty-one".