221668 has 12 divisors (see below), whose sum is σ = 391552. Its totient is φ = 109800.

The previous prime is 221659. The next prime is 221671. The reversal of 221668 is 866122.

221668 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

It is a hoax number, since the sum of its digits (25) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 421 + ... + 787.

2²²¹⁶⁶⁸ is an apocalyptic number.

It is an amenable number.

221668 is a deficient number, since it is larger than the sum of its proper divisors (169884).

221668 is a wasteful number, since it uses less digits than its factorization.

221668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 522 (or 520 counting only the distinct ones).

The product of its digits is 1152, while the sum is 25.

The square root of 221668 is about 470.8163123767. The cubic root of 221668 is about 60.5202900777.

The spelling of 221668 in words is "two hundred twenty-one thousand, six hundred sixty-eight".