66211717 has 16 divisors (see below), whose sum is σ = 78785280. Its totient is φ = 54849600.

The previous prime is 66211711. The next prime is 66211721. The reversal of 66211717 is 71711266.

It is not a de Polignac number, because 66211717 - 2¹¹ = 66209669 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66211711) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8367 + ... + 14227.

It is an arithmetic number, because the mean of its divisors is an integer number (4924080).

Almost surely, 2^66211717 is an apocalyptic number.

It is an amenable number.

66211717 is a deficient number, since it is larger than the sum of its proper divisors (12573563).

66211717 is a wasteful number, since it uses less digits than its factorization.

66211717 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5964.

The product of its digits is 3528, while the sum is 31.

The square root of 66211717 is about 8137.0582522187. The cubic root of 66211717 is about 404.5556616416. Note that the first 3 decimals are identical.

It can be divided in two parts, 6621 and 1717, that added together give a palindrome (8338).

The spelling of 66211717 in words is "sixty-six million, two hundred eleven thousand, seven hundred seventeen".