11709187681 has 9 divisors (see below), whose sum is σ = 11784220473. Its totient is φ = 11634631680.

The previous prime is 11709187643. The next prime is 11709187687. The reversal of 11709187681 is 18678190711.

The square root of 11709187681 is 108209.

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

It can be written as a sum of positive squares in 4 ways, for example, as 1580778081 + 10128409600 = 39759^2 + 100640^2 .

It is not a de Polignac number, because 11709187681 - 2¹¹ = 11709185633 is a prime.

It is a super-2 number, since 2×11709187681² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11709187687) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 26078145 + ... + 26078593.

Almost surely, 2^11709187681 is an apocalyptic number.

11709187681 is the 108209-th square number.

11709187681 is the 54105-th centered octagonal number.

It is an amenable number.

11709187681 is a deficient number, since it is larger than the sum of its proper divisors (75032792).

11709187681 is an frugal number, since it uses more digits than its factorization.

11709187681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1380 (or 690 counting only the distinct ones).

The product of its (nonzero) digits is 169344, while the sum is 49.

Multiplying 11709187681 by its sum of digits (49), we get a square (573750196369 = 757463²).

The spelling of 11709187681 in words is "eleven billion, seven hundred nine million, one hundred eighty-seven thousand, six hundred eighty-one".