221066 has 4 divisors (see below), whose sum is σ = 331602. Its totient is φ = 110532.

The previous prime is 221059. The next prime is 221069. The reversal of 221066 is 660122.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 660122 = 2 ⋅330061.

It can be written as a sum of positive squares in only one way, i.e., 172225 + 48841 = 415^2 + 221^2 .

It is a plaindrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (221069) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55265 + ... + 55268.

2²²¹⁰⁶⁶ is an apocalyptic number.

221066 is a deficient number, since it is larger than the sum of its proper divisors (110536).

221066 is a wasteful number, since it uses less digits than its factorization.

221066 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110535.

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

The square root of 221066 is about 470.1765625805. The cubic root of 221066 is about 60.4654539475.

Adding to 221066 its reverse (660122), we get a palindrome (881188).

The spelling of 221066 in words is "two hundred twenty-one thousand, sixty-six".