66605665603 has 4 divisors (see below), whose sum is σ = 66606217048. Its totient is φ = 66605114160.

The previous prime is 66605665601. The next prime is 66605665619. The reversal of 66605665603 is 30656650666.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 30656650666 = 2 ⋅15328325333.

It is a cyclic number.

It is not a de Polignac number, because 66605665603 - 2¹ = 66605665601 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66605665601) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7701 + ... + 365062.

It is an arithmetic number, because the mean of its divisors is an integer number (16651554262).

Almost surely, 2^66605665603 is an apocalyptic number.

66605665603 is a deficient number, since it is larger than the sum of its proper divisors (551445).

66605665603 is a wasteful number, since it uses less digits than its factorization.

66605665603 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 551444.

The product of its (nonzero) digits is 3499200, while the sum is 49.

The spelling of 66605665603 in words is "sixty-six billion, six hundred five million, six hundred sixty-five thousand, six hundred three".