221655636445666 has 32 divisors (see below), whose sum is σ = 336718648019520. Its totient is φ = 109425864397056.

The previous prime is 221655636445657. The next prime is 221655636445667. The reversal of 221655636445666 is 666544636556122.

It is not an unprimeable number, because it can be changed into a prime (221655636445667) 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, 55990725 + ... + 59818663.

It is an arithmetic number, because the mean of its divisors is an integer number (10522457750610).

Almost surely, 2^{221655636445666} is an apocalyptic number.

221655636445666 is a deficient number, since it is larger than the sum of its proper divisors (115063011573854).

221655636445666 is a wasteful number, since it uses less digits than its factorization.

221655636445666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3829218.

The product of its digits is 1119744000, while the sum is 67.

The spelling of 221655636445666 in words is "two hundred twenty-one trillion, six hundred fifty-five billion, six hundred thirty-six million, four hundred forty-five thousand, six hundred sixty-six".