11161056581 has 2 divisors, whose sum is σ = 11161056582. Its totient is φ = 11161056580.

The previous prime is 11161056559. The next prime is 11161056701. The reversal of 11161056581 is 18565016111.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10018008100 + 1143048481 = 100090^2 + 33809^2 .

It is a cyclic number.

It is not a de Polignac number, because 11161056581 - 2²⁶ = 11093947717 is a prime.

It is a super-2 number, since 2×11161056581² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11161050581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5580528290 + 5580528291.

It is an arithmetic number, because the mean of its divisors is an integer number (5580528291).

Almost surely, 2^11161056581 is an apocalyptic number.

It is an amenable number.

11161056581 is a deficient number, since it is larger than the sum of its proper divisors (1).

11161056581 is an equidigital number, since it uses as much as digits as its factorization.

11161056581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7200, while the sum is 35.

The spelling of 11161056581 in words is "eleven billion, one hundred sixty-one million, fifty-six thousand, five hundred eighty-one".