11721344666 has 4 divisors (see below), whose sum is σ = 17582017002. Its totient is φ = 5860672332.

The previous prime is 11721344659. The next prime is 11721344669. The reversal of 11721344666 is 66644312711.

11721344666 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 an emirpimes, since its reverse is a distinct semiprime: 66644312711 = 353 ⋅188794087.

It can be written as a sum of positive squares in only one way, i.e., 11648669041 + 72675625 = 107929^2 + 8525^2 .

It is not an unprimeable number, because it can be changed into a prime (11721344669) 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 as a sum of consecutive naturals, namely, 2930336165 + ... + 2930336168.

Almost surely, 2^11721344666 is an apocalyptic number.

11721344666 is a deficient number, since it is larger than the sum of its proper divisors (5860672336).

11721344666 is an equidigital number, since it uses as much as digits as its factorization.

11721344666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5860672335.

The product of its digits is 145152, while the sum is 41.

The spelling of 11721344666 in words is "eleven billion, seven hundred twenty-one million, three hundred forty-four thousand, six hundred sixty-six".