66991619966 has 8 divisors (see below), whose sum is σ = 101482355304. Its totient is φ = 33164168200.

The previous prime is 66991619957. The next prime is 66991619971.

66991619966 is nontrivially palindromic in base 10.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 66991619896 and 66991619905.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 165820640 + ... + 165821043.

It is an arithmetic number, because the mean of its divisors is an integer number (12685294413).

Almost surely, 2^66991619966 is an apocalyptic number.

66991619966 is a deficient number, since it is larger than the sum of its proper divisors (34490735338).

66991619966 is a wasteful number, since it uses less digits than its factorization.

66991619966 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 331641786.

The product of its digits is 51018336, while the sum is 68.

The spelling of 66991619966 in words is "sixty-six billion, nine hundred ninety-one million, six hundred nineteen thousand, nine hundred sixty-six".