11199720561 has 4 divisors (see below), whose sum is σ = 14932960752. Its totient is φ = 7466480372.

The previous prime is 11199720541. The next prime is 11199720577. The reversal of 11199720561 is 16502799111.

It is a happy number.

11199720561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 11199720561 - 2²² = 11195526257 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (11199720541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1866620091 + ... + 1866620096.

It is an arithmetic number, because the mean of its divisors is an integer number (3733240188).

Almost surely, 2^11199720561 is an apocalyptic number.

It is an amenable number.

11199720561 is a deficient number, since it is larger than the sum of its proper divisors (3733240191).

11199720561 is an equidigital number, since it uses as much as digits as its factorization.

11199720561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3733240190.

The product of its (nonzero) digits is 34020, while the sum is 42.

The spelling of 11199720561 in words is "eleven billion, one hundred ninety-nine million, seven hundred twenty thousand, five hundred sixty-one".