221321166 has 16 divisors (see below), whose sum is σ = 482882688. Its totient is φ = 67067000.

The previous prime is 221321159. The next prime is 221321209. The reversal of 221321166 is 661123122.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1676610 + ... + 1676741.

It is an arithmetic number, because the mean of its divisors is an integer number (30180168).

Almost surely, 2^221321166 is an apocalyptic number.

221321166 is an abundant number, since it is smaller than the sum of its proper divisors (261561522).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

221321166 is a wasteful number, since it uses less digits than its factorization.

221321166 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3353367.

The product of its digits is 864, while the sum is 24.

The square root of 221321166 is about 14876.8668072279. The cubic root of 221321166 is about 604.8870913764.

Adding to 221321166 its reverse (661123122), we get a palindrome (882444288).

The spelling of 221321166 in words is "two hundred twenty-one million, three hundred twenty-one thousand, one hundred sixty-six".