217742819666 has 8 divisors (see below), whose sum is σ = 326631550080. Its totient is φ = 108865636308.

The previous prime is 217742819663. The next prime is 217742819687. The reversal of 217742819666 is 666918247712.

217742819666 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a super-2 number, since 2×217742819666² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (217742819663) 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, 2839466 + ... + 2915141.

It is an arithmetic number, because the mean of its divisors is an integer number (40828943760).

Almost surely, 2^217742819666 is an apocalyptic number.

217742819666 is a deficient number, since it is larger than the sum of its proper divisors (108888730414).

217742819666 is a wasteful number, since it uses less digits than its factorization.

217742819666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5773528.

The product of its digits is 12192768, while the sum is 59.

The spelling of 217742819666 in words is "two hundred seventeen billion, seven hundred forty-two million, eight hundred nineteen thousand, six hundred sixty-six".