11565066681 has 63 divisors (see below), whose sum is σ = 20206145631. Its totient is φ = 6596995104.

The previous prime is 11565066679. The next prime is 11565066707. The reversal of 11565066681 is 18666056511.

The square root of 11565066681 is 107541.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 1906108281 + 9658958400 = 43659^2 + 98280^2 .

It is a tau number, because it is divible by the number of its divisors (63).

It is not a de Polignac number, because 11565066681 - 2¹ = 11565066679 is a prime.

It is a super-2 number, since 2×11565066681² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (11565061681) by changing a digit.

It is a polite number, since it can be written in 62 ways as a sum of consecutive naturals, for example, 20324965 + ... + 20325533.

Almost surely, 2^11565066681 is an apocalyptic number.

11565066681 is the 107541-st square number.

11565066681 is the 53771-st centered octagonal number.

It is an amenable number.

11565066681 is a deficient number, since it is larger than the sum of its proper divisors (8641078950).

11565066681 is an frugal number, since it uses more digits than its factorization.

11565066681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1170 (or 579 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 45.

The spelling of 11565066681 in words is "eleven billion, five hundred sixty-five million, sixty-six thousand, six hundred eighty-one".