221606 has 16 divisors (see below), whose sum is σ = 414720. Its totient is φ = 86280.

The previous prime is 221603. The next prime is 221621. The reversal of 221606 is 606122.

221606 = T₉₉ + T₁₀₀ + ... + T₁₃₁.

221606 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 inconsummate number, since it does not exist a number n which divided by its sum of digits gives 221606.

It is not an unprimeable number, because it can be changed into a prime (221603) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 566 + ... + 873.

It is an arithmetic number, because the mean of its divisors is an integer number (25920).

2²²¹⁶⁰⁶ is an apocalyptic number.

221606 is a deficient number, since it is larger than the sum of its proper divisors (193114).

221606 is a wasteful number, since it uses less digits than its factorization.

221606 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1459.

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 221606 is about 470.7504646838. The cubic root of 221606 is about 60.5146470923.

Adding to 221606 its reverse (606122), we get a palindrome (827728).

The spelling of 221606 in words is "two hundred twenty-one thousand, six hundred six".