221666001764566 has 8 divisors (see below), whose sum is σ = 333256403565360. Its totient is φ = 110580533909448.

The previous prime is 221666001764563. The next prime is 221666001764573. The reversal of 221666001764566 is 665467100666122.

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

It is a self number, because there is not a number n which added to its sum of digits gives 221666001764566.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221666001764563) 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, 126233485321 + ... + 126233487076.

It is an arithmetic number, because the mean of its divisors is an integer number (41657050445670).

Almost surely, 2^{221666001764566} is an apocalyptic number.

221666001764566 is a deficient number, since it is larger than the sum of its proper divisors (111590401800794).

221666001764566 is a wasteful number, since it uses less digits than its factorization.

221666001764566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 252466972838.

The product of its (nonzero) digits is 26127360, while the sum is 58.

The spelling of 221666001764566 in words is "two hundred twenty-one trillion, six hundred sixty-six billion, one million, seven hundred sixty-four thousand, five hundred sixty-six".