66611111999 has 4 divisors (see below), whose sum is σ = 67233645864. Its totient is φ = 65988578136.

The previous prime is 66611111993. The next prime is 66611112011. The reversal of 66611111999 is 99911111666.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 66611111999 - 2³² = 62316144703 is a prime.

66611111999 is a strobogrammatic number because it is the same when read upside-down.

It is a Duffinian number.

It is a zygodrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66611111993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 311266772 + ... + 311266985.

It is an arithmetic number, because the mean of its divisors is an integer number (16808411466).

Almost surely, 2^66611111999 is an apocalyptic number.

66611111999 is a deficient number, since it is larger than the sum of its proper divisors (622533865).

66611111999 is a wasteful number, since it uses less digits than its factorization.

66611111999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 622533864.

The product of its digits is 157464, while the sum is 50.

The spelling of 66611111999 in words is "sixty-six billion, six hundred eleven million, one hundred eleven thousand, nine hundred ninety-nine".