221222220 has 24 divisors (see below), whose sum is σ = 619422384. Its totient is φ = 58992576.

The previous prime is 221222213. The next prime is 221222249. The reversal of 221222220 is 22222122.

221222220 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 221222220.

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, 1843459 + ... + 1843578.

It is an arithmetic number, because the mean of its divisors is an integer number (25809266).

Almost surely, 2^221222220 is an apocalyptic number.

221222220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221222220 is an abundant number, since it is smaller than the sum of its proper divisors (398200164).

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

221222220 is a wasteful number, since it uses less digits than its factorization.

221222220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3687049 (or 3687047 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 15.

The square root of 221222220 is about 14873.5409368449. The cubic root of 221222220 is about 604.7969356981.

Adding to 221222220 its reverse (22222122), we get a palindrome (243444342).

It can be divided in two parts, 22122 and 2220, that added together give a palindrome (24342).

The spelling of 221222220 in words is "two hundred twenty-one million, two hundred twenty-two thousand, two hundred twenty".