221212120 has 16 divisors (see below), whose sum is σ = 497727360. Its totient is φ = 88484832.

The previous prime is 221212111. The next prime is 221212129. The reversal of 221212120 is 21212122.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (221212111) and next prime (221212129).

It is a self number, because there is not a number n which added to its sum of digits gives 221212120.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221212129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2765112 + ... + 2765191.

It is an arithmetic number, because the mean of its divisors is an integer number (31107960).

Almost surely, 2^221212120 is an apocalyptic number.

221212120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221212120 is an abundant number, since it is smaller than the sum of its proper divisors (276515240).

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

221212120 is a wasteful number, since it uses less digits than its factorization.

221212120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5530314 (or 5530310 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 221212120 is about 14873.2014038673. The cubic root of 221212120 is about 604.7877314659.

Adding to 221212120 its reverse (21212122), we get a palindrome (242424242).

The spelling of 221212120 in words is "two hundred twenty-one million, two hundred twelve thousand, one hundred twenty".