221606668 has 6 divisors (see below), whose sum is σ = 387811676. Its totient is φ = 110803332.

The previous prime is 221606573. The next prime is 221606669. The reversal of 221606668 is 866606122.

221606668 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (221606669) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27700830 + ... + 27700837.

Almost surely, 2^221606668 is an apocalyptic number.

It is an amenable number.

221606668 is a deficient number, since it is larger than the sum of its proper divisors (166205008).

221606668 is a wasteful number, since it uses less digits than its factorization.

221606668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55401671 (or 55401669 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 37.

The square root of 221606668 is about 14886.4592163483. The cubic root of 221606668 is about 605.1470789649.

The spelling of 221606668 in words is "two hundred twenty-one million, six hundred six thousand, six hundred sixty-eight".