221212 has 12 divisors (see below), whose sum is σ = 400680. Its totient is φ = 106736.

The previous prime is 221209. The next prime is 221219. The reversal of 221212 is 212122.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221219) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 838 + ... + 1069.

It is an arithmetic number, because the mean of its divisors is an integer number (33390).

2²²¹²¹² is an apocalyptic number.

It is an amenable number.

221212 is a deficient number, since it is larger than the sum of its proper divisors (179468).

221212 is a wasteful number, since it uses less digits than its factorization.

221212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1940 (or 1938 counting only the distinct ones).

The product of its digits is 16, while the sum is 10.

The square root of 221212 is about 470.3317977768. The cubic root of 221212 is about 60.4787622107.

Adding to 221212 its reverse (212122), we get a palindrome (433334).

It can be divided in two parts, 2 and 21212, that multiplied together give a palindrome (42424).

The spelling of 221212 in words is "two hundred twenty-one thousand, two hundred twelve", and thus it is an iban number.