221666106565564 has 6 divisors (see below), whose sum is σ = 387915686489744. Its totient is φ = 110833053282780.

The previous prime is 221666106565489. The next prime is 221666106565609. The reversal of 221666106565564 is 465565601666122.

221666106565564 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27708263320692 + ... + 27708263320699.

Almost surely, 2^{221666106565564} is an apocalyptic number.

It is an amenable number.

221666106565564 is a deficient number, since it is larger than the sum of its proper divisors (166249579924180).

221666106565564 is a wasteful number, since it uses less digits than its factorization.

221666106565564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55416526641395 (or 55416526641393 counting only the distinct ones).

The product of its (nonzero) digits is 93312000, while the sum is 61.

The spelling of 221666106565564 in words is "two hundred twenty-one trillion, six hundred sixty-six billion, one hundred six million, five hundred sixty-five thousand, five hundred sixty-four".