11647764721 has 2 divisors, whose sum is σ = 11647764722. Its totient is φ = 11647764720.

The previous prime is 11647764697. The next prime is 11647764773. The reversal of 11647764721 is 12746774611.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11640036321 + 7728400 = 107889^2 + 2780^2 .

It is an emirp because it is prime and its reverse (12746774611) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 11647764721 - 2¹⁷ = 11647633649 is a prime.

It is not a weakly prime, because it can be changed into another prime (11647765721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5823882360 + 5823882361.

It is an arithmetic number, because the mean of its divisors is an integer number (5823882361).

Almost surely, 2^11647764721 is an apocalyptic number.

It is an amenable number.

11647764721 is a deficient number, since it is larger than the sum of its proper divisors (1).

11647764721 is an equidigital number, since it uses as much as digits as its factorization.

11647764721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 395136, while the sum is 46.

The spelling of 11647764721 in words is "eleven billion, six hundred forty-seven million, seven hundred sixty-four thousand, seven hundred twenty-one".