11765718721 has 2 divisors, whose sum is σ = 11765718722. Its totient is φ = 11765718720.

The previous prime is 11765718719. The next prime is 11765718733. The reversal of 11765718721 is 12781756711.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11677828096 + 87890625 = 108064^2 + 9375^2 .

It is an emirp because it is prime and its reverse (12781756711) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 11765718721 - 2¹ = 11765718719 is a prime.

Together with 11765718719, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (11765718521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5882859360 + 5882859361.

It is an arithmetic number, because the mean of its divisors is an integer number (5882859361).

Almost surely, 2^11765718721 is an apocalyptic number.

It is an amenable number.

11765718721 is a deficient number, since it is larger than the sum of its proper divisors (1).

11765718721 is an equidigital number, since it uses as much as digits as its factorization.

11765718721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 164640, while the sum is 46.

The spelling of 11765718721 in words is "eleven billion, seven hundred sixty-five million, seven hundred eighteen thousand, seven hundred twenty-one".